Allah Ta'ala orders in the Holy Quran in Surah Nisa:
O Believers! Obey Allah and obey the Messenger (blessings and peace be upon him) and those (men of Truth) who hold command among you. Surah Nisa (4:59)
Here ‘men of Truth’ means the Imams and the Legislators, as has been said by Hadhrat Abdullah Bin Abbas, Hadhrat Jabir Bin Abdullah, Hadhrat Hasan Basri, Hadhrat Ata Bin Abi Rabah, Hadhrat Ata Bin Saib, Hadhrat Abul A’aliyya (May Allah be well pleased with them). This verse allows establishes the compulsory nature of Taqleed.
If you yourselves do not know (anything), then ask the People of Remembrance. Surah Nahl (16:43)
Imam Jalaluddin Suyuti, in Durr al Manthoor, in the exegesis of this verse deduces from a Hadith that ‘men of truth’ means the Imams of the age.
Hadhrat Abu Najeeh ((May Allah Ta’ala shower His mercy on him) narrates on the authority of the great Tabi'e Imam Mujahid that ‘men of truth’ means the men of discernment (tafqa), intellect and understanding i.e. jurisprudents.
The teacher of Imam Bukhari’s teachers, Imam Abdur Razzaq writes in his collection of Tafseer:
Translation: 'Men of truth’ means the Jurisprudents and the scholars.
Hadhrat Imam Abu Jafar Tabari writes in Jame Ul Bayan Fi Tafseer Il Quran on the authority of Hadhrat Abdullah bin Abbas, Hadhrat Jabir bin Abdullah, Hadhrat Hasan Basri, Hadhrat Ata Bin Saib, Hadhrat Abul A’aliyya that ‘men of truth’ means the Jurisprudents and the scholars.
The author of Tafseer Kabeer, Hadhrat Imam Razi writes on the authority of Hadhrat Abdullah bin Abbas, Hadhrat Hasan Basri, Hadhrat Imam Mujahid and Hadhrat Imam Zahhak ((May Allah Ta’ala shower His mercy on him) that "men of truth" means the scholars who teach the rules of Shariah and instruct the people in matters of religion.
He also says that there is no disagreement over this, that a group of the Companions (Sahabah) and the tabien (Successors) that ‘men of truth ’means scholars.
Imam Ibn E Katheer, whose opinion is considered by those who don’t follow any Imam as the final word, writes in Tafseer e Katheer:
The "men of truth" meant here are the Jurisprudents (Fuqaha) and this is also the opinion of Hadhrat Imam Mujahid, Hadhrat Imam ‘Ata, Hadhrat Hasan Basri, Hadhrat Abu Ya’ala (May Allah shower their Mercy on them) that "men of truth" mean the scholars and the Fuqaha.