(And the Jews say the Christians follow nothing (true)…) [2:113].
This was revealed about the Jews of Medina and the Christians of Najran. When the delegation of Najran came to the Messenger of Allah, Allah bless him and give him peace, the Jewish rabbis came to see them. They had a debate with each other and the debate got so heated up that they shouted at each other. The Jews said: “You are not following the true religion”, and declared their disbelief in Jesus and the Gospel. In response, the Christians said: “You are not following the true religion”, and declared their disbelief in Moses and the Torah. Allah therefore revealed this verse.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou