425 – He said, “Now, suppose you contend that disagreement is allowable in this matter.”
426 – I replied, “You have just claimed that the dispute of each side generates two rulings, even though a moment ago you insisted that disagreement can yield only one ruling.”
427 – He asked, “And what do you yourself say?”
428 – I said, “Disagreement is of two kinds:
429 – “If there is an explicit text from Allah, a sunnah of His Messenger, or a consensus of the Muslims, it is impermissible for anyone who knows of any of these proofs to oppose it.
430 – “But if none of those three proofs is present, the scholars may exercise ijtihad, seeking a close parallel to one of those sources.
431 – “Once a qualified person has exercised ijtihad, he may pronounce according to the evidence he has found, provided it falls under the purport of a verse, a sunnah, or consensus.
432 – “If an ambiguous case arises that can bear two distinct rulings, and one mujtahid’s conclusion differs from another’s, each may act on his own conclusion; such instances, however, are rare upon close examination.”
433 – He said, “What evidence supports what you have said?”
434 – I answered, “My evidence is reasoning from the Quran, the Sunnah, and consensus.”
435 – He said, “Then set out the distinction between the rulings that concern disagreement.”
436 – I said, “Allah—exalted is He—says: ‘And do not be like those who split and differed after clear proofs had come to them’ (Āl ʿImrān 3:105);
437 – and He also says: ‘Those who were given the Scripture did not divide until after…’ (Al-Bayyinah 98:4).”