Back 
Surah 3. Aal-Imran
Ayah 69 - 71
69وَدَّت طَّآئِفَةٌ مِّنْ أَهْلِ ٱلْكِتَـٰبِ لَوْ يُضِلُّونَكُمْ وَمَا يُضِلُّونَ إِلَّآ أَنفُسَهُمْ وَمَا يَشْعُرُونَ
70يَـٰٓأَهْلَ ٱلْكِتَـٰبِ لِمَ تَكْفُرُونَ بِـَٔايَـٰتِ ٱللَّهِ وَأَنتُمْ تَشْهَدُونَ
71يَـٰٓأَهْلَ ٱلْكِتَـٰبِ لِمَ تَلْبِسُونَ ٱلْحَقَّ بِٱلْبَـٰطِلِ وَتَكْتُمُونَ ٱلْحَقَّ وَأَنتُمْ تَعْلَمُونَ
[69-71] (O Believers,) a party of the people of the Book longs to lead you astray, somehow or other; whereas they mislead none except themselves, but they do not perceive it. O people of the Book, why do you deny Allah's Signs, which you yourselves are witnessing?60 O people of the Book, why do you confound the Truth with falsehood and conceal the Truth knowingly?
60There may be another rendering of this sentence: "You yourselves testify these." But in neither case is the sense of the passage affected. The fact is that the pious life of the Holy Prophet and the marvelous effects which his precepts and example were producing on the lives of his Companions, and the high and sublime teachings of the Qur'an, were all such clear Signs of God that no one, who was familiar with the lives of the Prophets and with the nature of the heavenly Scriptures, could possibly doubt or deny his Prophethood. Thus, in fact, many a people of the Book (especially the learned among them) had realized that Muhammad (Allah's peace be upon him) was the same Prophet whose coming had been foretold by the former Prophets. So much so, that they were at times completely overpowered by the force of the plain Truth, and would unwittingly admit and confirm that the teachings of the Holy Prophet were true. That is why, the Qur'an accuses them time and again of obduracy and deliberate rejection of the Truth after seeing clear Signs of God and being fully convinced of it in their hearts.