وَقَالَ الَّذِينَ كَفَرُوا لَوْلَا نُزِّلَ عَلَيْهِ الْقُرْآنُ جُمْلَةً وَاحِدَةً ۚ كَذَٰلِكَ لِنُثَبِّتَ بِهِ فُؤَادَكَ ۖ وَرَتَّلْنَاهُ تَرْتِيلًا 32
Those who reject Faith say: "Why is not the Qur'an revealed to him all at once? Thus (is it revealed), that We may strengthen thy heart thereby, and We have rehearsed it to thee in slow, well-arranged stages, gradually.