And ‘Umar (or Ibn ‘Umar), may Allah be pleased with them both, used to trim the mustache so much that the whiteness of the skin would become visible, and the hair between the mustache and the beard (on the chin), meaning the hair in the middle, he would have them cut off.

Narrated Ibn `Umar: The Prophet said, "To get the moustaches cut 'short is characteristic of the Fitra."