It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "Gabriel (peace be upon him) taught me the Qur'an on one mode (harf). I kept requesting him for more, and he kept increasing it for me until it reached seven modes, and then he stopped." Zuhri said that the meaning and purpose of these seven modes is the same, and there is no difference between them regarding what is lawful and unlawful.