Nature of the Qur'an

A guidance (to the God-fearing, believing, steadfastly praying and contributing)
2. This is the Book; in it is guidance sure, without doubt, to those who fear God;

3. Who believe in the Unseen, are steadfast in prayer, and spend out of what We have provided for them;

4. And who believe in the Revelation sent to thee, and sent before thy time, and (in their hearts) have the assurance of the Hereafter.

(Surah 2, The Cow)