J Those who were given the Book did not become divided until after the clear proof had come unto them.
4 This verse is similar to 45:17: And We gave them clear proofs from the Command. And they differed not till after knowledge had come unto them, out of envy among themselves (cf. 2:213; 3:19, 105; 10:93; 23:53; 43:63-65). Given this tendency among human beings, 3:105 counsels, Be not like those who became divided and differed after the clear proofs had come to them. From one perspective, this means that people had been unified in their disbelief, but that after the clear proofs of revelation came, they differed: among them were those who believed, and among them were those who disbelieved (2:253). Others claim that it alludes to those among the People of the Book who believed that a messenger would come, but, when the Prophet Muhammad was sent, denied his prophethood, as in 2:89: And when there came to them a Book from God, confirming that which they had with them—and aforetime they used to ask
for victory over those who disbelieve—so when there came to them that which they recognized, they disbelieved in it (R). Others see this verse as a reference to the corruption of pure revelation by previous religious communities, who argued with one another and divided into different sects (firqah; IK), as in 11:110; 27:76; and 41:45. In this vein they cite a famous ḥadīth, “Verily, the Jews differed until they became seventy-one sects. And verily, the Christians differed until they became seventy-two sects. And this community [i.e., the Muslim community] will divide into seventy-three sects, and all of them will be in the Fire except one.” The Prophet was then asked, “Who are they, O Messenger of God?” He replied, “[Those who follow] what I and my Companions follow” (IK, Q).