Musnad Ahmad 1153:403

Al-Khuza'i and Abu Sa'id narrated to us, they said: Sa'id ibn Muslim ibn Banik narrated to us, he said: 'Amir ibn 'Abd Allah ibn al-Zubayr narrated to us, from 'Awf ibn al-Harith, who said: Al-Khuza'i, the son of 'Aisha's brother through her mother, said: From 'Aisha, that the Messenger of Allah, peace and blessings of Allah be upon him, said: "O 'Aisha, beware of the belittled sins, for indeed there is a seeker for them from Allah, the Almighty and Majestic."