No hadith with such meaning was found, although there are some hadiths about the last two verses of Surah Inshirah, فإذا فرغت فانصب وإلی ربک فارغب that have been mentioned in hadithic-tafsir books (books that have collected hadiths that explain and interpret quranic verses) such as Tafsir-al-Burhan, Tafsir-al-Thaqalain, etc. These hadiths interpret the above-mentioned verses like this: “When you are done with your prophethood, appoint Ali (a.s.) for the people.”. In another hadith, regarding the first verse of this surah, Imam Sadiq says: “The expansion of the Prophet’s chest lies in the wilayah (religious authority) of Ali (a.s.).”.
These hadiths are all authentic because their narrators all have been depended on and considered muwathaq (trustworthy) by Rijal scholars (scholars who are familiar with all of the different narrators in Islamic history and can tell which can be depended on and which can’t). Narrators like Ibn Abi-Umayr who is of the Mashayekh-ul-Thuqat (Out of the thousands of Shia narrators out there, only five of them are considered mashayekh-ul-thuqat. This term is used for very highly dependable and trustworthy narrators.). Of course, there are numerous chapters in hadith books on the high virtue of Imam Ali (a.s.) that convey the same meaning as the hadiths mentioned above. For instance, there is a chapter in Kitab-ul-Hujjah of Osool-ul-Kafi named “The direct and indirect appointment of Ali (a.s.)” and a chapter in unit 39 of volume 36 of Bihar-ul-Anwar that mentions verses that have been revealed regarding Imam Ali (a.s.).
What these hadiths exactly do is show where these verses apply and what their instances are, they aren’t after interpreting the verses or explaining their words and phrases.
No hadith was found with such a meaning (We made Imam Ali (a.s.) like this in order for him to become your son-in-law) in Osool Kafi nor in any other resources. But there are traditions in our hadiths and hadithic-tafsir books (books that have collected hadiths that explain and interpret quranic verses) such as Tafsir al-Burhan and Tafsir al-Thaqalain in relation with Surah Inshirah that are about Imam Ali (a.s.). For instance, there are about 17 hadiths in Tafsir al-Burhan. We will analyze some of these to see if they are correct or not.
1) Mohammad ibn Hasan narrates from Ahmad ibn Muhammad, from ibn Abi Umayr, from Jamil from Hasan ibn Rashed that Imam Sadiq (a.s.) said regarding the first verse of Surah Inshirah (ألم نشرح لک صدرک): “بولایة امیرالمؤمنین”. Meaning that the expansion of the Prophet’s (p.b.u.h.) chest lies in the wilayah (religious authority) of Imam Ali (a.s.).
2) In another hadith Muhammad ibn Humam narrates from Ibrahim ibn Hashem, from ibn Abi Umayr that Imam Sadiq says regarding the abovementioned verse that:
“بعلی فاجعله وصیاً”. Meaning that: “Oh Prophet (p.b.u.h.), did we not expand your chest by giving you Ali (a.s.), so appoint him as your successor.” In other words, the verse is saying: the expansion of the Prophet’s (p.b.u.h.) chest lied in Imam Ali (a.s.).
Concerning the verse (فإذا فرغت فانصب – “when you are done, appoint”), he goes on to say: “Allah (s.w.t.) ordered the Prophet (p.b.u.h.) to first establish prayer, zakat, fasting, hajj etc., and then ordered him to appoint Imam Ali (a.s.) as his successor afterwards.”
3) It has been narrated from Mufazzal ibn Umar that Imam Sadiq said that the verse is saying: “فإذا فرغت فانصب علیاً بالولایة” “When you are done, appoint Imam Ali (a.s.) as successor”.
These three hadiths were only examples and there are many hadiths on the high virtue of Imam Ali (a.s.). But the hadiths regarding Surah Inshirah are all similar to the ones mentioned above in saying that the expansion of the Prophet’s chest lies in the wilayah of Imam Ali (a.s.) and that the finalization and completion of Islam is in the appointment of Ali (a.s.) as successor and imam.
Concerning the authenticity of these hadiths, one must say that narrators like Ibn Abi Umayr are in the sanad (chain of narrators) of these hadiths who are of the Mashayekh-ul-Thuqat (Out of the thousands of Shia narrators out there, only five of them are considered mashayekh-ul-thuqat. This term is used for very highly dependable and trustworthy narrators.) in which rijal scholars all have considered thiqah (trustworthy and dependable in their narrations). Moreover, the number of these hadiths is so high that one becomes sure that that they can’t all be unauthentic.
One subject which is very important and should be noted, relates to the way these hadiths are explaining the verses of the Quran. In reality, many of the hadiths mentioned in our hadithic-tafsir books such as Tafsir Burhan and Tafsir Nur-ul-Thaqalain which are considered hadiths that are interpreting the Quran, aren’t trying to interpret the Quran. The interpretation of the Quran means to explain its words and phrases. Most of these hadiths aren’t like that. What these hadiths really do is apply the verses of the Quran and find some of their instances and examples and in many cases, show their clearest instances. Therefore, assuming that these hadiths are correct and authentic and have been issued in normal conditions (not in sensitive conditions such as taqiyyah), they don’t narrow down the broad meaning of the verses that might cover many instances, because disclosing some examples for a verse doesn’t mean that there aren’t any more and doesn’t cause the interpreter not to be able to find anymore. That is the meaning of a verse having a broad meaning with many different instances.
Therefore, one must say that one of the instances in which the Prophet’s chest has been expanded, is the appointment of Imam Ali (a.s.) for the people.
Also, it must be noted that there are other viewpoints regarding this issue. For further information, we recommend the book Shenakht-e-Quran by Ayatullah Gerami.
 Seyyid Hashem Hoseini Bahrani, al-Burhan fi Tafsir al-Quran, v.4, pg. 474, Isma’iliyan Publications.
 Ibid. Also see: Ta’wil al-Ayat al-Dhahirah, pg. 787 and Bihar-ul-Anwar, v.36, pg. 136.
 Al-Burhan fi Tafsir al-Quran, v.4, pg.475. Also see: Osool-ul-Kafi, v.1, pg. 294, hadith 3.
 Sheikh Muhammad Mudhaffari, Al-Fawa’id al-Rijaliyyah, print of Islamic Seminary of Qum pg. 73.
 Javadi Amoli, Tafsir Tasnim, v.1, pg. 168, Publication Center of Isra’.
 In this book, the vastness of Quranic concepts in comparison with common and everyday concepts has been put to discussion.