the faithless say why has not the quran been sent down to him all at once? so it was that we may strengthen your heart with it and we have recited it in a measured tone.
وقال الذين كفروا لولا نزل عليه القرآن جملة واحدة كذلك لنثبت به فؤادك ورتلناه ترتيلا