Adnan Oktar (Harun Yahya) One of the qualities of believers mentioned in the Qur'an is their belief in the Books of God. As our Lord revealed the Qur'an to our Prophet (pbuh), He also revealed the Gospel to the Prophet Jesus (pbuh), the Torah to the Prophet Moses (pbuh), various texts to the Prophet Abraham (pbuh), and the Psalms to the Prophet David (pbuh). Muslims are obliged to believe in all these Divine books.
God states the following in the verses of the Qur'an:
Those who believe in what has been sent down to you and what was sent down before you, and are certain about the hereafter. (Surat al-Baqara, 4)