Musnad Ahmad 1153:1247

Muhammad ibn Abdullah narrated to us, Isra'il narrated to us, from Simak, from Ikrimah, from Aisha, who said: The Messenger of Allah (peace and blessings of Allah be upon him) used to raise his hands in supplication until I heard him say: "O Allah, I am only a human being, so do not punish me for the cursing of any man among the Muslims if I have harmed him."