Musnad Ahmad 514:1

'Abd al-Samad narrated to us, Hammad—meaning Ibn Salamah—narrated to us, al-Jurayri narrated to us, from Abu Nadrah: That a man from the companions of the Prophet, peace and blessings of Allah be upon him, who was called Abu 'Abd Allah, his companions entered upon him to visit him while he was weeping. They said to him, "What makes you weep? 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 grasped a handful with His right hand, and another with the other hand, and said: "This is for this, and this is for this, and I do not care."' So I do not know in which of the two handfuls I am."