Malachi 2:14

2:14 Yet you ask, “Why?” The Lord is testifying against you on behalf of the wife you married when you were young, ¹  to whom you have become unfaithful even though she is your companion and wife by law. ² 

Malachi 3:7

3:7 From the days of your ancestors you have ignored ³  my commandments ⁴  and have not kept them! Return to me, and I will return to you,” says the Lord who rules over all. “But you say, ‘How should we return?’

[2:14]  ¹ tn Heb “the Lord is a witness between you and [between] the wife of your youth.”

[2:14]  ² sn Though there is no explicit reference to marriage vows in the OT (but see Job 7:13; Prov 2:17; Ezek 16:8), the term law (Heb “covenant”) here asserts that such vows or agreements must have existed. References to divorce documents (e.g., Deut 24:1-3; Jer 3:8) also presuppose the existence of marriage documents.

[3:7]  ³ tn Heb “turned aside from.”

[3:7]  ⁴ tn Or “statutes” (so NAB, NASB, NRSV); NIV “decrees”; NLT “laws.”