Musannaf Ibn Abi Shayba 7:200

Ibn Numayr narrated to us, from Yahya ibn Sa'id, from Mansur, from 'Abd al-Rahman, from his mother, that she asked 'A'ishah, may Allah be pleased with her: "What expiates a person's statement, 'All my wealth is in the path of Allah,' or 'in the curtain of the Ka'bah'?" She said: "It is expiated by what expiates an oath."