It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both): I used to write down everything I heard from the Messenger of Allah (peace and blessings be upon him) in order to memorise it. Then Quraysh stopped me and said: "Do you write down everything you hear from the Messenger of Allah (peace and blessings be upon him), while the Messenger of Allah (peace and blessings be upon him) is a human being who speaks in (both states of) contentment and anger?" So I stopped and mentioned this to the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Write, for by the One in whose Hand is my soul, nothing but the truth has come out of it (this mouth)," and he (peace and blessings be upon him) pointed with his blessed hand to his blessed mouth. The two Shaykhs used all the narrators of this hadith as evidence except al-Walid, and I think he is al-Walid bin Abi al-Walid al-Shami; if so, Imam Muslim used him as evidence.