It is narrated from Yahya bin Saeed that he said: I and Muhammad bin Yahya bin Haban were sitting, so Muhammad called a man and said: Relate what you have heard from your father. That man said: My father went to Sayyiduna Zaid bin Thabit (may Allah be pleased with him) and asked him, "How is it to complete the recitation of the Word of Allah in seven days?" He replied: "It is good, but in my view, completing it in fifteen or twenty days is better." He said, "Ask me why?" So I asked, "Why?" Sayyiduna Zaid (may Allah be pleased with him) said: "So that I may understand it and remember it."