(Who is guilty of more wrong than he who forgeth a lie against Allah, or saith: I am inspired…) [6:93].
This was revealed about the liar, Musaylimah al-Hanafi. This man was a soothsayer who composed rhymed speech and claimed prophethood. He claimed that he was inspired by Allah.
(… and who saith: I will reveal the like of that which Allah hath revealed?) [6:93].
This verse was revealed about 'Abd Allah ibn Sa'd ibn Abi Sarh. This man had declared his faith in Islam and so the Messenger of Allah, Allah bless him and give him peace, called him one day to write something for him. When the verses regarding the believers were revealed (Verily, We created man from a product of wet earth…) [23:12-14], the Prophet dictated them to him. When he reached up to (and then produced it as another creation), 'Abd Allah expressed his amazement at the precision of man's creation by saying (So blessed be Allah, the Best of Creators!). The Messenger of Allah, Allah bless him and give him peace, said: “This ['Abd Allah's last expression] is how it was revealed to me”. At that point, doubt crept into 'Abd Allah. He said: “If Muhammad is truthful, then I was inspired just as he was; and if he is lying, I have uttered exactly what he did utter”. Hence Allah's words (and who saith: I will reveal the like of that which Allah hath revealed). The man renounced Islam. This is also the opinion of Ibn 'Abbas according to the report of al-Kalbi.
'Abd al-Rahman ibn 'Abdan informed us> Muhammad ibn 'Abd Allah ibn Nu'aym> Muhammad ibn Ya'qub al-Umawi> Ahmad ibn 'Abd al-Jabbar> Yunus ibn Bukayr> Muhammad ibn Ishaq> Shurahbil ibn Sa'd who said: “This verse was revealed about 'Abd Allah ibn Sa'd ibn Abi Sarh. The latter said: 'I will reveal the like of that which Allah has revealed', and renounced Islam. When the Messenger of Allah, Allah bless him and give him peace, entered Mecca, this man fled to 'Uthman [ibn 'Affan] who was his milk brother. 'Uthman hid him until the people of Mecca felt safe. He then took him to the Messenger of Allah, Allah bless him and give him peace, and secured an amnesty for him”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou