Maliks Muwatta Book 049, Hadith Number 004.

Section : Sunna of the Fitra.

Yahya related to me from Malik from Yahya ibn Said that Said ibn al-Musayyub said, "Ibrahim, may Allah bless him and grant him peace, was the first to give hospitality to the guest and the first person to be circumcised and the first person to trim the moustache and the first person to see grey hair. He said, 'O Lord! What is this?' Allah the Blessed, the Exalted, said, 'It is dignity, Ibrahim.' He said, 'Lord, increase me in dignity!'"

Yahya said that he had heard Malik say, "One takes from the moustache until the edge of the lip appears, that is the rim. One does not cut if off completely so that one mutilates oneself."