Musnad Ahmad 937:224

Hassan narrated to us, Ibn Lahi'ah narrated to us, Al-Harith ibn Yazid narrated to us, he said: I heard Ibn Hujayrah the elder saying: Someone informed me who heard Abu Dharr saying: I conversed privately with the Messenger of Allah, peace and blessings of Allah be upon him, one night until the morning. I said: "O Messenger of Allah, command me." He said: "It is a trust, and a disgrace, and a regret on the Day of Resurrection, except for the one who takes it by its right and fulfills what is upon him regarding it."