And from his narration on the authority of Ibn 'Abbas that he said upon the interpretation of Allah's saying (Sad.): '(Sad.) He says: Sad by the Qur'an, i.e. repeat the Qur'an until you distinguish between faith and disbelief, the prophetic wont and blameworthy innovation, truthfulness and lying, the lawful and the unlawful, good and evil; it is also said that Sad stands for barring (sadd) from the guidance, i.e. the barring of the people of Mecca from the Truth and guidance; it is also said that it stands for Abu Jahl; and it is also said that it stands for truthful (sadiq) in his speech; and it is also said that Sad is one of Allah's names; and it is also said that it is an oath by which Allah swore (By the renowned Qur'an) by the Qur'an which possesses honour and clarity of exposition; it is an honour to those who believe in it and it is a clear exposition of the people of old as well as of future generations of people. Allah swore by the Qur'an,
