'Deal Treacherously' in the Bible

Have we not all one father? hath not one God created us? why do we deal treacherously every man against his brother, by profaning the covenant of our fathers?

And did he not make one? Yet had he the residue of the spirit. And why one? That he might seek a godly seed. Therefore take heed to your spirit, and let none deal treacherously against the wife of his youth.