How can the Qur’an's affirmation of the authenticity of the Torah and the Gospel be reconciled with its simultaneous assertion of their corruption?

Belief in the Torah, the Gospel, and other heavenly books that Allah revealed to His prophets is one of the pillars of faith. A Muslim's faith is not complete without it. There is no contradiction between believing in the origin of these books and that they were revealed by Allah Almighty, and what has occurred in them now of falsification and distortion, for the Quran informed about the alteration by the People of the Book.