Musannaf Ibn Abi Shayba 3:3628

Waki’ narrated to us, from Ibn Abi Dhi’b, from al-Aswad ibn al-‘Ala’ ibn Harithah, from Abu Salamah, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "From the moment one of you leaves his house for his mosque, one foot records a good deed, and the other erases a bad deed."