'Covenant' in the Bible

And ye have known that I have sent unto you this charge, For My covenant being with Levi, Said Jehovah of Hosts.

My covenant hath been with him of life and of peace, And I make them to him a fear, and he doth fear Me, And because of My name he hath been affrighted.

And ye, ye have turned from the way, Ye have caused many to stumble in the law, Ye have corrupted the covenant of Levi, Said Jehovah of Hosts.

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?

Lo, I am sending My messenger, And he hath prepared a way before Me, And suddenly come in unto his temple Doth the Lord whom ye are seeking, Even the messenger of the covenant, Whom ye are desiring, Lo, he is coming, said Jehovah of Hosts.