It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that a man asked the Messenger of Allah (peace and blessings be upon him): "What do you say about this saying of Allah, the Mighty and Majestic: 'Just as We sent down (punishment) upon those who divided' - who are 'those who divided'?" He (peace and blessings be upon him) said: "The Jews and the Christians." He asked: "'Those who made the Qur'an into pieces' - what is meant by making it into pieces?" He (peace and blessings be upon him) said: "That they believed in part (of the Book) and disbelieved in part."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Habib bin Hassan except Humayd bin Hammad bin Khuwar, and no one narrated it from Abu Zabyan as marfu' (attributed to the Prophet) except Habib bin Hassan. Whereas al-A'mash narrated it from Abu Zabyan, from Sayyiduna Ibn Abbas (may Allah be pleased with them both), as mawquf (the Companion's own words)."
Hadith Referenceالمعجم الأوسط / باب الميم / 6204
Hadith Takhrij«أخرجه البخاري فى «صحيحه» برقم: 4706، والحاكم فى «المستدرك» برقم: 3374»