Musnad Ahmad 26:106

Yahya narrated to us, from al-Taymi, from Abu Uthman, from Ibn Mas’ud: A man kissed a woman, so he came to the Prophet, peace and blessings of Allah be upon him, asking him about its expiation. Then Allah, the Mighty and Majestic, revealed: "And establish prayer at the two ends of the day and at the approach of the night. Indeed, good deeds do away with misdeeds" [Hud: 114]. He said: "O Messenger of Allah, is this for me?" He said: "For whoever among my nation does such [an act]."