Musannaf Ibn Abi Shayba 13:852

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: ‘Umar ibn Dharr narrated to us, he said: Al-Qasim ibn ‘Abd al-Rahman used to make a man swear an oath regarding what he was withholding from him of a right that he knew belonged to him. And Al-Sha’bi said regarding the unrestricted oath: Its sin and its righteousness are only upon what one intended.