An act that prophets do to prove their prophethood that normal individuals aren’t capable of doing is called a “miracle”.
The Holy Quran is the greatest miracle of Prophet Muhammad (pbuh). In the Quran, there are numerous verses that speak of and prove it being a miracle. In addition to the many verses that are miracles themselves other than the fact that they are verses of the Quran (eg. the verses that predict the future, those that speak of past nations, very high concepts and teachings etc.). The people back then learned of these different matters through the verses that were revealed to the Prophet (pbuh). In the Quran, two other miracles of the Prophet (pbuh) have also been spoken of; the first being his ascension to the skies and heavens, and the second being him splitting the moon by pointing to it which has been indicated in the beginning of surah Qamar.
In Arabic, the term miracle literally means to make another unable to do something and in religious terms means for one to do something or say something that others are unable of doing or saying. Therefore, the phenomenon that divine prophets would do in order to prove their prophethood that others were unable of doing are all miracles, like the awakening of the dead that Prophet Isa (pbuh) would do, or like the staff of Prophet Musa (pbuh) that would turn into a python.
The Prophet of Islam had many miracles in his lifetime, to the extent that they have counted four thousand miracles for him. His greatest miracle is the Holy Quran that in contrast to the miracles of other prophets, and in contrast to other miracles of his own, is an eternal and never-ending miracle that will remain for all time and eras. It is a book of miracles in different dimensions; it has unique eloquence, and expresses the highest divine teachings and concepts etc. that scholars and commentators have all thoroughly discussed about. The best reason for the Quran being a miracle is its challenging others to bring a surah like it: “And if you are in doubt concerning what We have sent down to Our servant, then bring a surah like it, and invoke your helpers besides Allah, should you be truthful.” No one has been able to bring a surah like it till today, and no one will be able to do so forever. Also, the Quran’s predictions of the future are another example of it being a miracle and since all of these news of the future and the unseen were first disclosed by the Prophet (pbuh) they can be considered his miracles. Some of these predictions that have been mentioned in the Quran are as follows:
1- In order to receive charities, a group of the Bani Asad tribe converted to Islam, but hadn’t truly embraced Islam in their hearts. When they came to the Prophet (pbuh) and claimed that they have become Muslim, the Prophet recited the following verse: “The Bedouins say," We have faith." Say," You do not have faith yet; rather say," We have embraced Islam," for faith has not yet entered into your hearts…” Knowing what is going on in others’ hearts is truly a miracle.
2- Aas ibn Wa’il would insult the Prophet (pbuh) and call him “abtar” (cut off in progeny) because of him not having a son. The Prophet (pbuh) said that Aas is the true “abtar” and called his own progeny the “Kawthar”. This prediction came out to be true and it was Aas’s progeny who was cut off, but the Prophet’s progeny is still alive till today (there are seyyids all over the world today).
3- The Prophet (pbuh) informed of the defeat of the Roman empire to the
within a few years…”, and this vow actually took place and after a few years it was the Romans who defeated the Persians.
The Holy Quran has mentioned two of the Prophet’s miracles:
1- His ascension to the skies and heavens (Mi’raj): “Immaculate is He who carried His servant on a journey by night from the Sacred Mosque to the Farthest Mosque whose environs We have blessed…”
This verse is about when Allah (swt) brought the Prophet (pbuh) to
The Mi’raj (ascension) of the Prophet (pbuh) was his miracle and after returning from it, he gave many news of the unseen.
All Islamic scholars say that the Mi’raj took place before his migration from Makkah to Medinah although there is a difference of opinion on exactly what year it took place; the years that have been claimed are: the second year of his prophethood, the third, fifth, and sixth year and other years have also been claimed.
Also, according to the Quran, the Mi’raj began from Masjidul-Haram in Makkah, although some believe that the house of Umm Hani or the Valley of Abi-Taleb (where the Prophet and his companions were surrounded and suffered sanctions for three years and were put under extreme pressures by their tribe during the advent of Islam). It is possible to say that his first Mi’raj was from Makkah and that the second was from the home of Umm Hani, but there is no evidence that any of his Mi’rajes took place from the Valley of Abi-Taleb.
Another important point about the Prophet’s Mu’raj is that there is also a debate on whether his ascension was a spiritual one or one of the body and soul together.
What most commentators believe is that it was an ascension of the soul and body together. Meaning that the Prophet (pbuh) was transferred with his materialistic body from the Masjidul-Haram to the Mosque of Jerusalem, and ascended to the skies and heavens from there with the same body and witnessed many of the unseen there and mentioned them for the people when he returned. For further information on the true essence of the Prophet’s Mi’raj, one can refer to tafsir books.
2- Shaqqul-Qamar or the splitting of the moon:
Allah (swt) has mentioned this great miracle of His prophet (pbuh) in the beginning of Surah Qamar saying: “The hour (of the day of judgement) drew near and the moon was split”
The story goes like this: The disbelievers of Makkah (before hijrah [the migration to Madinah]) asked the Prophet (pbuh) for a sign saying: “If you are truly the messenger of God, then split the moon into two halves.” The Prophet (pbuh) replied: “If I do so, will you believe?” They all agreed. That night was a night in which the moon was a complete one. The Prophet (pbuh) asked his lord for the moon to be split into two halves. He pointed to the moon and it surprisingly split and many were a witness of this miracle, yet the disbelievers denied this miracle and falsely claimed that Muhammad (pbuh) has bewitched them. The Quran considers the denial of the disbelievers a normal habit saying: “If they see a sign, they turn away, and say," An incessant magic!" They denied, and followed their own desires, and every matter has a setting [appropriate to it]. There have already come to them reports containing admonishment.”
This is part of the matters pertaining to the miracles of our prophet (pbuh).
 Baqarah:23 “وَ إِن کُنتُمْ فىِ رَیْبٍ مِّمَّا نَزَّلْنَا عَلىَ عَبْدِنَا فَأْتُواْ بِسُورَةٍ مِّن مِّثْلِهِ وَ ادْعُواْ شُهَدَاءَکُم مِّن دُونِ اللَّهِ إِن کُنتُمْ صَادِقِین”
 Mohammad Baqir Majlisi, Biharul-Anwar, vol. 17, pg. 199.
 Hujurat:14. “قَالَتِ الْأَعْرَابُ ءَامَنَّا قُل لَّمْ تُؤْمِنُواْ وَ لَاکِن قُولُواْ أَسْلَمْنَا وَ لَمَّا یَدْخُلِ الْایمَانُ فىِ قُلُوبِکُمْ”
 Kawthar:3 “إِنَّ شَانِئَکَ هُوَ الْأَبْتر”
 Biharul-Anwar, vol. 17, pg. 203.
 Rum:1-3. “غُلِبَتِ الرُّومُ،فىِ أَدْنىَ الْأَرْضِ وَ هُم مِّن بَعْدِ غَلَبِهِمْ سَیَغْلِبُون”
 Isra:1. “سُبْحَانَ الَّذِى أَسْرَى بِعَبْدِهِ لَیْلًا مِّنَ الْمَسْجِدِ الْحَرَامِ إِلىَ الْمَسْجِدِ الْأَقْصَا الَّذِى بَارَکْنَا حَوْلَهُ لِنرُِیَهُ مِنْ ءَایَاتِنَا إِنَّهُ هُوَ السَّمِیعُ الْبَصِیر”
 Najm:7-9. “وَ هُوَ بِالْأُفُقِ الْأَعْلىَ، ثمَُّ دَنَا فَتَدَلىَ،فَکاَنَ قَابَ قَوْسَینِْ أَوْ أَدْنىَ، فَأَوْحَى إِلىَ عَبْدِهِ مَا أَوْحَى” Mohammad Husein Tabataba’I, Al-Mizan, vol. 19, pg. 38.
 “وَ لَقَدْ رَءَاهُ نَزْلَةً أُخْرَى،عِندَ سِدْرَةِ المْنتَهَى”
 Abd Ali Arusi Juwayzi, Nurul-Thaqalain, vol. 3, pg. 98, Ismailiyan Press,
 Seyyid Mahmoud Alousi, Ruhul-Ma’ani fi Tafsiril-Quranil-Adhim, vol. 8, pg. 8, Darul-Kutubil-Ilmiyyah Press,
 Translation of Al-Mizan, vol. 19, pg. 39.
 See: translation of Al-Mizan, under the first verse of surah Isra.
 Qamar:1. “اقْترَبَتِ السَّاعَةُ وَ انشَقَّ الْقَمَر”
 Fadhl ibn Hasan Tabarsi, translation of Majma’ul-Bayan, vol. 24, pg. 10.
 “وَ إِن یَرَوْاْ ءَایَةً یُعْرِضُواْ وَ یَقُولُواْ سِحْرٌ مُّسْتَمِرٌّ،وَ کَذَّبُواْ وَ اتَّبَعُواْ أَهْوَاءَهُمْ وَ کُلُّ أَمْرٍ مُّسْتَقِر”