Sahih al-Bukhari 4706
Narrated Ibn `Abbas concerning:
"As We have sent down (the Scripture) on those who are divided (Jews and Christians)." (15.90) They 
believed in part of it and disbelieved in the other, (and they) are the Jews and the Christians.
حَدَّثَنِي عُبَيْدُ اللَّهِ بْنُ مُوسَى، عَنِ الأَعْمَشِ، عَنْ أَبِي ظَبْيَانَ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ ‏{‏كَمَا أَنْزَلْنَا عَلَى الْمُقْتَسِمِينَ‏}‏ قَالَ آمَنُوا بِبَعْضٍ وَكَفَرُوا بِبَعْضٍ، الْيَهُودُ وَالنَّصَارَى‏.‏