'Deal Treacherously' in the Bible

Have we not all one father? Hath not our God prepared us? Wherefore do we deal treacherously, Each against his brother, To pollute the covenant of our fathers?

And He did not make one only, And He hath the remnant of the Spirit. And what is the one alone! He is seeking a godly seed. And ye have been watchful over your spirit, And with the wife of thy youth, None doth deal treacherously.

For I hate sending away, said Jehovah, God of Israel, And He who hath covered violence with his clothing, said Jehovah of Hosts, And ye have been watchful over your spirit, And ye do not deal treacherously.