The Prophet ﷺ said, "Differ from the polytheists. Let your beards grow full and trim your moustaches short."Whenever Ibn Umar performed Hajj or Umrah, he would grasp his beard in his fist, and whatever extended beyond it he would cut off.In another narration, "Trim the moustaches closely and let the beards grow."
عن النبي ﷺ قال: خالفوا المشركين؛ وفروا اللحى، وأحفوا الشوارب. وكان ابن عمر إذا حج أو اعتمر قبض على لحيته، فما فضل أخذه. وفي رواية: أنهكوا الشوارب، وأعفوا اللحى.
Bukhari related it in the Book of Clothing (5892, 5893), and this is his wording. Muslim related it in the Book of Purification (259), where it reads, "Trim closely the mustaches, and let the beards grow." In another wording, "Trim closely the mustaches, and let the beards grow full," and in another wording, from the Prophet ﷺ, that he commanded trimming the mustache closely and letting the beard grow. Muslim did not mention that Ibn Umar, when he performed Hajj or Umrah, would grasp his beard and cut off whatever exceeded his grip. Bukhari related this with the same chain mentioned previously.Malik also recorded it in Muwatta, in the Book of Hajj (187), from Nafi, that Abdullah bin Umar, when he shaved his head during Hajj or Umrah, would trim from his beard and mustache.The meaning of trimming the mustache closely is that it should be cut until it is close and thin. It may also mean being thorough in cutting it, from the expression "ahfaytu in the matter," meaning I was thorough in it. This was pointed out by Khattabi.It will come later, in the hadith of Abu Hurairah, "Cut the mustaches short." Jazz means clipping wool from a sheep, and it does not involve thoroughness or complete removal. For this reason, many of the early scholars held that shaving it off completely was forbidden, among them Imam Malik, who held the view that whoever shaved it should be disciplined. So the preferred practice is to clip it until the edge of the lip becomes visible, or to trim it closely.Imam Ahmad was asked, "Do you think a man should take his mustache and trim it closely, or how should he take it?" He said, "If he trims it closely, there is no harm, and if he clips it short, there is no harm."