'Faithless' in the Bible

Judah has been treacherous (disloyal), and an repulsive act has been committed in Israel and in Jerusalem; for Judah has profaned the sanctuary of the Lord which He loves, and has married the daughter of a foreign god.

But you say, “Why [does He reject it]?” Because the Lord has been a witness between you and the wife of your youth, against whom you have dealt treacherously. Yet she is your marriage companion and the wife of your covenant [made by your vows].

But not one has done so who has a remnant of the Spirit. And what did that one do while seeking a godly offspring? Take heed then to your spirit, and let no one deal treacherously against the wife of your youth.