Promoting and expanding the spiritual and material sciences is one of the important issue during the time of Imam Mahdi (ajtf). The knowledge will reach the highest level during that time, according to Imam Sadiq (as).
In the name of Allah
Question 022: Is Imam Mahdi (ajtf) going to bring a new Shari’ah?
Answer 022: Promoting and expanding the spiritual and material sciences is one of the important issue during the time of Imam Mahdi (ajtf). The knowledge will reach the highest level during that time, according to Imam Sadiq (as).
A great cultural revolution will occur by Imam Mahdi (ajtf). As mentioned in some Ahadith, the ratio of all the sciences known by man to the sciences which Imam Mahdi (ajtf) will discover is 2 to 27. This means that although we have made great progress, is not highly knowledgeable. This means, that Imam Mahdi (ajtf) will expand the knowledge completely. It doesn’t mean that the Shari’ah is incomplete and then Imam Mahdi (ajtf) will complete it! So, during the time of Imam Mahdi (ajtf), those who are eager and capable to learn more knowledge and participate in classes, they will reach the highest level of knowledge.
The Arabic version of this hadith is as follows:
«الْعِلْمُ سَبْعَةٌ وَ عِشْرُونَ حَرْفاً فَجَمِیعُ مَا جَاءَتْ بِهِ الرُّسُلُ حَرْفَانِ فَلَمْ یَعْرِفِ النَّاسُ حَتَّى الْیَوْمِ غَیْرَ الْحَرْفَیْنِ فَإِذَا قَامَ قَائِمُنَا أَخْرَجَ الْخَمْسَةَ وَ الْعِشْرِینَ حَرْفاً فَبَثَّهَا فِی النَّاسِ وَ ضَمَّ إِلَیْهَا الْحَرْفَیْنِ حَتَّى یَبُثَّهَا سَبْعَةً وَ عِشْرِینَ حَرْفاً»
The following are some hadith in which mentioned that Imam Mahdi (ajtf) will bring new religion:
Imam Baqir (as) said: When Imam Mahdi (as) appears He will bring new order, new method and new judgment with Him.
یَقُومُ الْقَائِمُ بِأَمْرٍ جَدِیدٍ وَ کِتَابٍ جَدِیدٍ وَ قَضَاءٍ جَدِیدٍ
Imam Sadiq (as) said: Imam Mahdi (as) will do the same act that the Holy Prophet (pbuh) done. As the holy Prophet (pbuh) that destroyed the act of Jaheliyyah (ignorance), the Imam will destroy current innovations (bid’ah) and then rejuvenates Islam.
The Arabic version of this hadith:
قَالَ يَصْنَعُ مَا صَنَعَ رَسُولُ اللَّهِ يَهْدِمُ مَا كَانَ قَبْلَهُ كَمَا هَدَمَ رَسُولُ اللَّهِ أَمْرَ الْجَاهِلِيَّةِ وَ يَسْتَأْنِفُ الْإِسْلَامَ جَدِيداً
Some translators have mistakenly translated that He (ajtf) will appear with new book, a new Shari’ah. Because, the phrase “یستأنف الاسلام جدیدا” doesn’t mean new religion, it means rejuvenates Islam.
It clear that the newness of these programs, methods and judgments is not because he brings new religion with him, but exits Islam from the congestion of superstitions, distortions and incorrect interpretations and false understandings in the way that it appears like a completely new building
In the Holy Quran Allah (swt) says: “Truly, the Perfect Religion in The Sight of Allah is Islam.” Also, Allah (swt) says: “Muhammad is not the father of [any] of your men, but [he is] the Messenger of Allah, and the Seal of the Prophets. And Allah has full knowledge of all things.” 
According to the following issues, we see that Imam Mahdi (ajtf) is the leader who guides us toward the right path.
«إِذَا قَامَ الْقَائِمُ (ع) دَعَا النَّاسَ إِلَی الْإِسْلَامِ جَدِیداً وَ هَدَاهُمْ إِلَی أَمْرٍ قَدْ دَثَرَ وَ ضَلَّ عَنْهُ الْجُمْهُورُ وَ إِنَّمَا سُمِّیَ الْقَائِمُ مَهْدِیّاً لِأَنَّهُ یُهْدَی إِلَی أَمْرٍ مَضْلُولٍ عَنْهُ وَ سُمِّیَ الْقَائِمَ لِقِیَامِهِ بِالْحَقِّ»
Reasons: 1. Some traditions and rules have not been declared due to the lack of circumstances and conditions during the time of the Infallibles (pbuth). Imam Mahdi (ajtf) will explain them completely.
- Some rules have been removed from books of Ahadith and He (ajtf) will carry them out.
- Imam Mahdi (ajtf) will present the real rules as they seem unreal during the time of occultation, however, we must act based on them.
- Thanks to technology and other reasons which help people expand their knowledge of comprehending the Islamic teachings, they will have a lot of new questions which are required to be answered comprehensively.
- Mahdi (ajtf) is an imam, not a Prophet, Imam does not bring new Shari’ah.
- Since, people have deviated Islam over time from the original message of the Prophet (saw), or have misinterpreted it, but since Ahlul Bayt (pbuth) are qualified to interpret Quran they know much more than various caliphs, scholars, individuals over time – they also know which hadith are real and which are fabricated, etc. They know the proper intent without doubt.
Therefore, Imam Mahdi (ajtf) will appear and guide us based on the above mentioned issues. People think that He (ajtf) will bring a new method or a new Shari’ah, though the only Perfect Religion in The Sight of Allah (swt) is Islam and it has been completed.
For further information on this issue, please read the following answers:
Index: The Benefits of Imam Mahdi (ajtf) during His occultation, answer 026.
Index: The Signs of the Re-Emergence, according to ibn Mahziyar Ahwazi, answer 072.
Index: General appearance of Imam Mahdi (ajtf), answer 267.
Index: Possibility of Establishing Relationship with Imam Mahdi, answer 513.
 . Majlesi, Muhammad Baqir, Bihar al-Anwar, Vol. 52, Pgs. 336-364.
 . Ibn abi Zaynab (Nomani), Muhammad bin Ebrahim, al-Ghibah, researcher and editor: Ghaffari, Ali Akbar, Pg. 233, Sadouq publication, Tehran, first edition, 1397 A.H.
 . Majlesi, Muhammad Baqir, Bihar al-Anwar, Vol. 52, Pg. 352, Dar Ihya al-Turath al-Arabi, Beirut, second edition, 1403 A.H.
 . Surah Ali ‘Imran, verse 19; Surah Al-Ahzab, verse 40.