Ya ahla alkitabi lima takfuroona bi-ayati Allahi waantum tashhadoon (surah Al Imran: 70)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(3:70) O People of the Book! Why do you reject the signs of Allah even though you yourselves witness them? *60

Yaaa Ahlal Kitaabi lima takfuroona bi Aayaatil laahi wan antum tashadoon

*60). Another rendering of this could be, 'and you yourselves bear witness' to Muhammad's prophethood. However it is translated the sense remains the same. In fact, the impeccable purity of the life of the Prophet, the astounding impact of his teachings and training on the lives of his Companions, and the loftiness of the teachings of the Qur'an all constituted such illustrious signs of God that it was very difficult for anyone conversant with the lives of the Prophets and the tenor of Divine Scriptures to doubt the prophethood of Muhammad (peace be on him).
It is a fact that many Jews and Christians (especially their scholars) came, to recognize in their hearts that Muhammad was the very Prophet whose coming had been announced by the preceding Prophets. This fact was so overwhelming that, despite their intransigence, they could not help but give verbal expression, at times, to the truth of the Prophet's teachings. This is why the Qur'an repeatedly blames them for maliciously misrepresenting the signs of God which they saw with their own eyes and to which they themselves attested.