Al-Isra 17:106

Waqur-anan faraqnahulitaqraahu AAala annasi AAalamukthin wanazzalnahu tanzeela

And [it is] a Qur’ān which We have separated [by intervals] that you might recite it to the people over a prolonged period. And We have sent it down progressively.

We have divided the Qur’ān in portions, so that you may recite it to the people gradually, and We have revealed it little by little.