What is the ruling on praying behind one who adorns himself with what Allah has forbidden?

The questioner : What is the ruling on praying behind an imam who lets his garment hang below the ankles or adorns himself with gold, knowing the ruling?

The Shaykh : May Allah reward you, the prayer is valid; because the Messenger (peace and blessings be upon him) used to say regarding the imams: But the Muslim should choose to pray behind a righteous, knowledgeable, and reciting imam so that his prayer is as close as possible to perfection...

The questioner : Reciting, but adorning himself with gold and letting his garment hang below the ankles, O our Shaykh?

The Shaykh : You have received the answer—May Allah reward you—but now, after the answer, we say: He should choose a righteous, knowledgeable, and pious imam. If he prays behind such a man who adorns himself with what Allah has forbidden, that is a sin, and his sin is upon himself and his side; as our Lord (Mighty and Majestic) said in His Book: As for the prayer, it has no connection to such disobedience from this imam, like an imam who shaves his beard, for example, or prays in trousers or the like; his sin is upon him and not upon the worshippers behind him in any way. Yes.