All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
In their books, the scholars of Usool Al-Fiqh (Fundamentals of Islamic Jurisprudence) underlined the ranks of people in this respect. Some people are classified as Mujtahid Mutlaq (a scholar competent for absolute Ijtihaad and scholarly reasoning), which is the highest rank, like the four Imams (Abu Haneefah, Maalik, Ash-Shaafiʻi, and Ahmad) and their like. There is also the rank of Mujtahid within his Imam’s school of Fiqh, as well as the Muqallid (follower of a certain Imam). The rank of Muqallid itself incorporates various ranks. Some of them have learned and studied the schools of Fiqh; they follow these schools and issue their Fataawa in accordance with the books of their scholars. It is permissible for the Muqallid of this rank to issue a Fatwa (in this manner) as long as he is versed in the subject matter of the Fatwa. There is also the rank of the lay-Muslim who does not possess adequate religious knowledge and qualifications to do any of the above, and there are many ranks in between.
Moreover, Ijtihaad is also divided into various categories, as explained by the scholars of Usool Al-Fiqh. A person may be classified as Mujtahid in a certain field of knowledge and Muqallid in others, and he can also be classified as Mujtahid in a certain Fiqhi issue only, and people are of endless ranks in respect with the knowledge that only Allah knows.
Anyway, none has the right to speak about the religion of Allah without knowledge. Therefore, whoever is capable of practicing Ijtihaad and can deduce the rulings independently (from the Sharee‘ah texts) may speak about the religion according to his rank, and whoever is below this rank, let him speak only within the scope of his knowledge. As for a Muqallid, he is required to seek the Fatwa of a trustworthy scholar and act upon his opinion. The duty of a seeker of knowledge is to follow the scholars whom he trusts until he is fully equipped to practice Ijtihaad in such a way that makes him able to understand the texts and deduce the rulings therefrom independently, and then he gets to join the rank of Mujtahid with regard to the Fiqhi questions in which he is qualified to practice Ijtihaad. The seekers of knowledge are of various ranks as well; some of them are closer to the rank of lay-Muslims given their inadequate knowledge, and others are closer to that of Mujtahid, and so on, according to the scope of people’s knowledge and qualifications to practice Ijtihaad.
Allah Knows best.