It is narrated from Hazrat Abu Bakrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: Jibreel and Mikaeel came to me. Jibreel said to me that the Noble Qur'an should be recited on one letter. Mikaeel said to request an increase in it. Then Jibreel said that you can recite the Noble Qur'an on seven letters, each of which is sufficient and complete, provided that you do not change a verse of mercy into punishment or a verse of punishment into mercy.