Musnad Ahmad 30:2209

'Affan narrated to us, he said: 'Abd al-Rahman ibn Ibrahim narrated to us, from al-'Ala', from his father, from Abu Hurayrah, who said: The Prophet, peace and blessings of Allah be upon him, was traveling on the road to Makkah, and he came upon Jumdan. He said: "This is Jumdan; proceed, the *mufarridun* have surpassed." They said: "And what are the *mufarridun*?" He said: "Those who remember Allah much." Then he said: "O Allah, forgive those who shave." They said: "And those who shorten?" He said: "O Allah, forgive those who shave." They said: "And those who shorten?" He said: "And those who shorten."