وَمِن قَبْلِهِ كِتَابُ مُوسَىٰ إِمَامًا وَرَ‌حْمَةً (And before this, there was the Book of Musa, a guide and a mercy. - 46:12) This verse, for one thing, gives proof of the statement mentioned in verse 9 that the Holy Prophet ﷺ is not an unprecedented messenger and Qur'an is not a singular divine Book which may create doubts in the minds. Sayyidna Musa (علیہ السلام) came before him as a messenger, and Torah was revealed to him which is accepted by all these Jews and Christians. Secondly, it supports the verse 10 above, because Sayyidna Musa (علیہ السلام) and Torah themselves are witnesses to the Holy Prophet ﷺ being the messenger of Allah and the Qur'an being Allah's Book.