According to search-discovered classical Islamic scholarship, the concept of the Holy Book (al-Kitab) refers to the divinely revealed scriptures sent by Allah to guide humanity through His prophets. Belief in these books is a cornerstone of Islamic faith. The Quran explicitly mentions several holy books, including the Tawrat (Torah) revealed to Musa, the Zabur (Psalms) to Dawud, the Injeel (Gospel) to Isa, and the Suhuf (Scrolls) to Ibrahim and Musa. Islamic theology, as explained by scholars like Ibn Kathir, asserts that while the original revelations were pure, previous scriptures have undergone alteration (tahrif). The Quran is held as the final, complete, and perfectly preserved revelation, confirming the core truths of its predecessors and serving as the ultimate guidance for all humanity. This unified understanding is derived from numerous Quranic verses and the consensus of Islamic scholars.