What is faith in books? What are the books that were revealed to allahs messengers?
God Almighty has revealed to His messengers texts that contain rulings on belief, worship, morals, and life in this world. “The folios of old (al-Suhuf al-Ula)” revealed to HE Abraham and HE Moses, the Torah, Psalms, Bible, and the Quran are revealed heavenly books.
 Al-Baqara (The Cow), 2: 85; Âli Imrân (The Family of Imran), 3: 3-4; An-Nisâ (Women), 4: 163; Tâ Hâ, 20: 133; An-Najm (The Star), 53: 36-37; Al-Hadîd (Iron), 57: 26-27; Al-A‘lâ (The Most High), 87: 18-19.
Source: Dr. Murat Kaya,The Final Divine Religion: ISLAM