The divine religions and ideologies have been changing towards getting more and more comprehensive across the passed ages and definitely the reason behind such changes is the growth of humans’ intellect, and no one can claim that such a thing hasn't happened regarding Islam, because not only hasn’t this growth of intellect come to an end, but has also gathered momentum; today’s human society and individuals who are the building blocks of society can in no way be compared to those of the advent of Islam. The rules that pertain to worshipping God can stay the same because they have to do with the creator and the nurturer of mankind and have nothing to do with the growth of the human intellect, but the social rules and laws and those that have to do with governing need to be updated, rules like punishment in Islamic penal law and blood money. The reason why Islam is the seal of all religions is not that it's rules will stay the same across time, but that man is no more in need of any form of divine revelation and Islam can guide mankind and help him legislate new rules and more efficient ones, this is why Islam is the seal of all religions...”, Please let me know where can I find the appropriate answer to the abovementioned theory and in which sources.
Paying attention to these points can be beneficial:
1- The fact that the prophet of Islam was the seal of prophets making Islam the seal of religions is pointed out in verse 40 of surah Ahzab, and what is meant is that there will be no prophets after the prophet of Islam.
2- The reason why Islam is the seal of all religions is that:
Firstly, it is an utterly comprehensive religion, because there was no limitation neither regarding the prophet that the religion was revealed upon, nor to the people it was sent to and those who practiced it, therefore Islam was able to explain all of what it had to say, and secondly, the fact that Islam was immune to alteration.
3- Islam consists of changing and stable elements. Distinguishing between the two is done through the method that the Imams have established which is known as "Ijtihad". Ijtihad and the immunity of the Quran (the key source of Islam) to distortion has prevented the alteration of this religion.
4- Deducing the global and unchanging elements of Islam, thus reaching its core, can only be accomplished through the right method, which is a fiqhi (jurisprudential) and analytic one, and the development of science and technology and other humanly sciences (that have nothing to do with religion) such as sociology, etc., have nothing to do with it. Of course, they can help with the changing and conditional elements which are the methods and instruments used to carry out religion, and their development will certainly have an impact on these elements, but at the same time, will not change the primary and unchanging ones to changing and unstable ones. It must be noted that it isn't true that the only stable elements in Islam are the ones related to worship and that all others are prone to change; there are many social and political Islamic laws that are also stable and unchanging.
5- What was mentioned above as the viewpoint of Mr. Soroosh is merely a conjecture that is not backed by any reasoning and the fundamentals of this theory have been challenged in many ways. This theory is based on conceiving the social laws of Islam as conditional and changing elements of Islam, on the ideology of secularism, etc., which all come from having a false picture and understanding of Islam.
6- As we explained before Islam, the seal of religions, wasn’t limited as far as the people it was sent for were concerned, but this does not mean that all people reach the amount of knowledge and intelligence to be able to comprehend and understand all of the truth in a correct manner, rather, it means that generally the people of the time of Islam's emergence bore the capacity to keep and protect their religion’s heritage.
First off, we need to know that:
1- The belief that Islam is the seal of religions is one of its fundaments that all Islamic sects agree on. Allah says in the Quran: " Muhammad is not the father of any of your men, but [he is] God's messenger and the Seal of the Prophets. God is Aware of everything! " “Khatam” (that is the Arabic word for seal) means anything that is used to bring an end to something, and also refers to the object used to seal papers and letters with because stamping (a letter) is done at its end, therefore the object used to do such is referred to as “khatam”. The reason why this word also means “ring” is because in the past people tended to carve their seal on their rings and would use the ring as a stamp. Therefore the interpretation of the word “khatam” which has been attributed to the prophet (pbuh) in the verse is that he is the seal of Prophets and there will be no prophet after him. Some Islamic scholars describe being the seal of religions like this: "الخاتم من ختم المراتب باسرها"; a prophet can be the seal of prophets if he has passed all levels, leaving no unachieved levels for him.
2- There has been a lot of debate about the truth of Khatamiyyah (sealing) and how a prophet can be the seal of all previous prophets. We believe that the human is God-seeking in essence, but at the same time this inner force that drives us towards God is not capable enough of guiding the human being precisely to the right path and right beliefs; all it is, is an inclination towards a God. Not only has Allah gifted us with our intellect that can be known as an inner “prophet”, but has also sent the outer prophets (His messengers) to clarify and explain what we cannot understand and reach on our own. All of these prophets were faced with two limits (the limitation of their capacities for receiving revelation and the limits of the minds and intellect of their people in understanding the truth) and one threat (the alteration and change of course of their religion), therefore every religion played two roles regarding the one preceding it, one was to supplement and complete it, and the other to correct it, and this was the case until the revelation of Islam. The significance of Islam was that not only wasn’t its prophet limited in receiving revelation, but his people also weren’t limited; add to that the fact that the religion was utterly immune to any alteration and distortion. In other words, the prophet chosen was at the highest level of knowledge and the grounds were ready for people to comprehend and understand the divine truth and to put it more precise, at least some of them had such an ability (and that is enough). With all of the abovementioned limitations gone, Islam was able to present the complete divine message and guidance that was presented partially by previous religions and became the seal of religions. As we know, the seal of religions must be immune and protected from alteration and this was done regarding Islam with the help of two things:
a) The immunity of the Quran to alteration
b) Establishing a method by which any one who is familiar with and refers to the original sources using it can have an authentic and original understanding of religion and its laws.
Divine religions consist of two elements from Shahid Muttahhari's point of view, permanent/stable elements and changing ones. The permanent and global elements, which do not vary with the change of time and place, deal with the nature and essence of humans that will always remain the same through the course of time (there are some things that all humans share, no matter the time, place, etc.). At the same time of course, divine religions have also paid attention to the changing and developing aspects of humans by legislating conditional and changing laws (laws that depend on time and place and aren't absolute). Distinguishing between the permanent elements and the changing ones is only possible through the method that the household of the prophet have established called Ijtihad; it is through this method that Islam answers all of the guidance related needs of humanity.
It is obvious that the expansion of jurisprudential issues today and the fact that they were less in the past is due to the variety and expansion of our needs today. It's wrong to assume that in order to fulfill our needs today, some of Islam’s stable elements must be forgotten and disregarded, or that these needs signify the “expiration” of those elements, in fact, all progress can be made when the divine teachings of prophets and the method that the household of the prophet established are observed.
Let's say a student learns math from different teachers little by little. Every one of them teaches him a certain part of math, and the last teacher teaches him a series/set of general and widely used rules in addition to adding, subtracting, multiplying and dividing and the rules pertaining to them, for example if any number is multiplied by zero the result will be zero, or the result of adding two numbers is always bigger than the result of subtracting those two numbers from each other and tens and hundreds of other similar principles. From that point on whatever new mathematical problems and equations this student solves is because of those main principles which he has received from his teacher and all of the new problems need to be dealt with according to those general rules if he wants to get the correct answer. It is correct to say that it was the last teacher who finished the job. Obviously no student will then claim that he is no longer in need of the teacher’s teachings and that he must focus on solving new mathematical problems, because first of all, solving new problems is done through adding, subtracting, etc., and second of all, the results must be in compliance with the teacher’s principles in order to guarantee their accuracy.
3- What is mentioned in Dr. Soroosh's theory regarding Islam being the seal of religions isn't a new one, the only thing new about it is the form and wording in which he presents it in, and in reality, what he says is an answer to the question that asks whether or not being the seal of all religions has to do with the social, scholarly and cultural conditions of its people? In response to this question, Dr. Soroush gives the same answer Iqbal Lahuri does, but in another form. He says: "Khatamiyyah (sealing of religion) means that people will reach a point of development in which they will no longer be in need of religion". Or “It means that the teachings of the prophets are so widely taught and accessible that people don't need a new prophet to teach them, exactly like the time when a student no longer needs a teacher because he himself has become one.
But Iqbal asserts that like other creatures who need their instinct to guide them in the beginning of their lives and little by little as their senses and intelligence develop and help them until they reach a point in which they do not need the guidance of their instinct any more, humanity today has put its “childhood” behind and is no longer in any need of revelation. He believes that through acting according to the teachings of the Quran, man will reach a point in which he will no longer be in any need of religion.
Among other atheists that have a similar viewpoint are the Marxists, they believe that the features of the people when Islam was revealed is why Islam is the seal of religions, and that it was ingenious of the prophet and because of his profound understanding that he announced that his religion was the seal of religions because he knew that there will come a time in which there will no longer be any need for religion as a result of man’s advance to a new level of understanding and knowledge.
4- Clearly, the answer Shahid Mutahhari gives to similar theories applies here too, because the only thing they prove is the end of religiosity, not the end of prophethood, moreover if we accept that the main reason for Khatamiyyahh is what Dr. Soroush has mentioned, it would entail:
1- The inclination of a vast majority of people towards true Islam, which we all know has not taken place.
2- The theological fundamentals and roots of the discussion of Khatamiyyahh like the definition of religion, the outcomes of religion, the reason behind sending prophets, the comprehensiveness of religion, the function of religion in social fields and the fulfillment of religion regarding all social and personal needs… need to change in a way so that they are in consistence with this theory; for example we will have to ignore the historical, Quranic, logical and hadithic evidence that tells us that the reason and philosophy of sending the prophets in addition to otherworldly affairs and statuses, is also for the management of worldly issues and the ones that have to do with the lives of people in this world, we will also have to believe in secularism and deny the completeness and comprehensiveness of religion and that it addresses both of these dimensions and also deny the fixedness of Islamic rules and laws owing to the great progress in technology and knowledge and believe in the “expansion and contraction of religion”, etc., while these beliefs have been seriously challenged; when the basis and underlying arguments of Khatamiyyah (Dr. Soroush’s interpretation) are challenged, it will entail the challenging Dr. Soroush’s theory on Khatamiyyah as well.
Therefore, not being limited in terms of a religion’s audience does not mean that all people which live in that era and time are capable of comprehending all of the truth correctly, but that when they are viewed as a whole they bear the capacity to receive and protect and maintain their religious heritage. In other words the seal of religions has to do with the situation of their society and features of their culture and knowledge, meaning that the grounds are ready for protecting and maintaining the religion by a group among those people that can present it to others when needed, not that there will be a time when religion’s teachings are known by all without any need to refer to it, and that they will preserve it without even knowing it.
5- As we explained before, Islam consists of the two elements of changing and permanent ones. What technology and the development of science can do are aid us in coming up with newer methods and instruments for carrying out religion, Nevertheless, when it comes to deriving the universal and unchanging elements of religion, they aren't up to the task, and it is the responsibility of a fiqhi and anqlytic method to do so, thus, all that needs to be up to date are tools and methods, not permanent elements of religion. At the same time, permanent elements are not only ones related to worship, but have to do with social and governmental rules too; so not all of Islam's social and governmental rules are temporary ones and there are many in which are permanent that outline the main structure and philosophy of Islam in different fields like society, economy and law.
 “...و لکن خاتم النبیین...” Ahzab:40.
 Majma’ul-Bahrain, vol. 6, pg. 53.
 See: Tafsir Nemouneh, vol. 17, pg. 339; translation of Al-Mizan, vol. 1, pg. 487; Misbah Yazdi, Amuzeshe Aqa’ed, pg. 288.
 Translation of Al-Mizan, vol. 16, pg. 487.
 Shahid Mutahhari, Khatamiyyat, pg. 70.
 For instance, Mulla Sadra considers Islam being the seal of religions to be the result of the completion of man’s mind (Sharhe Mulla Sadraye Shirazi bar Usule Kafi, pg. 110); the author of Javaherul-Kalam has criticized this view and has said that what is meant by being the seal of religions is that it is in harmony with all times and changes and is a universal religion that has addressed all issues. (Majma’ul-Rasa’el, pp. 9-11).
 Mahdi Hadavi Tehrani, Bavarha va Porsesha, pg. 41.
 For further information, see: Ibid, pp. 45-58.
 See: Ibid, pp. 30-31.
 Morteza Motahhari, Khatamiyyat, pp. 144-145.
 Bavarha va Porsesha, pp. 86-87.
 “Rishe dar Ab ast”, Kiyan Magazine, issue 29, pg. 5, quoted by Bavarha va Porsesha, pg. 36. Also, see: Baste Tajrobeye Nabavi, pg.95.
13] “Rishe dar Ab ast”, pp. 13-14 (with changes).
 Abdullah Nasri, Entazare Bashar az Din, pg. 106.
 Bavarha va Porsesha, pg. 35.
 Ibid, pg. 34.
 Ibid, pg. 37.
 See: Mohammad Taqi Misbah Yazdi, Amuzeshe Aqa’ed, pp. 11-12.
19] Religion, is a special method in which the benefit of the world lies that s in correspondence with otherworldly salvation and guarantees it (so there needs to be certain rules in religion that show us the way of life) translation of Al-Mizan, vol. 2, pg. 187..
 The goal behind sending the messengers is both social and individual perfection.
1- Abdul-Hosein KhosroPanah, Gostareye Shari’at; Entezare Bashar az Din.
2- Mahdi Hadavi Tehrani, Mabaniye Kalamiye Ejtehad.
3- Ali Rabbani Golpaygani, Jame’iyyat va Kamale Din.
 See: Entezare Bashar az Din, pp. 308-349 and 222-305.
 Ijtihad, a method for applying principles and general rules to contemporary issues, is one of the characteristics of Islam that doesn’t allow any issue remain without a ruling. Farhange Tashrihiye Estelahate Usul, Velayi, pp. 17-23.
 See: Bavarha va Porsesha, pp. 123-170.
 Reading the book Bavarha va Porsesha can help you in getting your answer.
 See: Mabaniye Kalamiye Ejtehad, pp. 383-405; Maktab va Nezame Eqtesadiye Islam, Mahdi Hadavi Tehrani, pp. 21-44.
1- Maktab va Nezame Eqtesadiye Islam, Mahdi Hadavi Tehrani.
2- Qezavat dar Islam, Mahdi Hadavi Tehrani.