Musnad Ahmad 514:2

'Affan narrated to us, Hammad ibn Salamah narrated to us, he said: Sa'id al-Jurayri informed us, from Abu Nadrah, who said: A man from the companions of the Messenger of Allah (peace and blessings of Allah be upon him) became ill, so his companions entered upon him to visit him, and he wept. It was said to him: "What makes you weep, O Abu 'Abd Allah? Did the Messenger of Allah (peace and blessings of Allah be upon him) not say to you: 'Trim your mustache, then leave it until you meet me'?" He said: "Yes, but I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: 'Indeed, Allah took a handful with His right hand and said: "This is for this, and I do not care." And He took another handful with His other hand and said: "This is for this, and I do not care."' So I do not know in which of the two handfuls I am."