Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) said to me: "Recite the Qur'an in forty days." Then he said, "Recite it in thirty days." Then he said, "Recite it in twenty days." Then he said, "If not, then in fifteen days." Then he said, "If not, then in ten days." Or, "Then in seven days." The Prophet (peace and blessings be upon him) concluded the matter at seven days.