Musnad Ahmad 27:221

Yahya narrated to us, from Ubaydullah, Nafi’ informed me, from Ibn Umar, from the Prophet (peace and blessings of Allah be upon him) who said: "Listening and obedience are upon the individual in what he loves or dislikes, unless he is commanded to commit a sin. If he is commanded to commit a sin, then there is no listening and no obedience."