Al-Khateeb (rahimahullaah) said: It is befitting for the beginner who seeks understanding that he is firmly established in what he acquires (of knowledge) and he should not take a lot.  He takes bit by bit in consideration of what he can memorise and comprehend; for indeed Allaah (The Most High) said: [وَقَالَ ٱلَّذِينَ كَفَرُواْ لَوۡلَا نُزِّلَ عَلَيۡهِ ٱلۡقُرۡءَانُ جُمۡلَةً۬ وَٲحِدَةً۬‌ۚ ڪَذَٲلِكَ لِنُثَبِّتَ بِهِۦ فُؤَادَكَ‌ۖ وَرَتَّلۡنَـٰهُ تَرۡتِيلاً۬ –And those who disbelieve say: “Why is not the Qur’an revealed to him all at once?” Thus (it is sent down in parts), that We may strengthen your heart thereby. And We have revealed it to you gradually, in stages] [25: 32]

Al-Faqee Wal-Mutafaqqih 2/100)