Recited in Stages
The disbelievers say, “Why was the Qur’an not sent down all at once?” We revealed it gradually to strengthen your heart, and We recited it in stages.
25:32And those who disbelieve say: Why is the Qur'an not revealed unto him all at once? (It is revealed) thus that We may strengthen thy heart therewith; and We have arranged it in right order.