Judah has broken faith; an abomination has been committed in Israel and in Jerusalem: Men were divorcing their wives to marry non-Israelite women for economic gain. These marriages allowed Jewish men to join existing merchant groups and trade networks when they returned from Babylonia. Malachi compares this unfaithfulness to idol worship.
In Israelite history, marrying foreign women often led to worshiping foreign gods. Loyalty was essential in Israel's agreements, both with God and in marriage. Divorce disrespects the unity of the marriage agreement (Malachi 2:15; see Genesis 2:24).