(And a party of the People of the Scripture say: Believe in that which hath been revealed unto those who believe…) [3:72].
Al-Hasan and al-Suddi said: “Twelve rabbis from the Jews of Khaybar and the town of ‘Uraynah conspired with each other, saying: ‘Pretend to join the religion of Muhammad at the beginning of the day and declare your disbelief in it at the end of the day. Say: ‘We have looked in our Scriptures and consulted our scholars and found that Muhammad is not genuine; it is clear to us now that he is lying and that his religion is false’. If you do this, his Companions will doubt their religion. They will say: these are people of the Book and they are more knowledgeable than us. They will then abandon their religion and embrace yours’. And so Allah, exalted is He, revealed this verse, thus informing His Prophet Muhammad, Allah bless him and give him peace, and the rest of the believers”.
Mujahid, Muqatil and al-Kalbi said: “This was revealed regarding the qiblah when it was changed toward the Ka‘bah. The Jews found it hard to accept that they were opposed, and so Ka‘b ibn al-Ashraf and his companions said: ‘Believe in that which was revealed to Muhammad regarding the matter of the Ka‘bah, pray toward it at the beginning of the day and then disbelieve in the Ka‘bah and return toward your qiblah at the end of the day. They might then say: these are people of the Book and they know better than us. They might then return to our qiblah’. Allah, exalted is He, warned His Prophet from the scheming of these people and informed him about what they were conspiring; He revealed (And a party of the People of the Scripture say…)”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou