Malachi2chapter 2

The first half is addressed to the priests, and it appeals to an ideal: the covenant of Levi, where the law of truth was in his mouth, he walked with God in peace, and turned many away from iniquity. "The priest's lips should keep knowledge, and they should seek the law at his mouth: for he is the messenger of the LORD of hosts." Priests were the teachers as well as the sacrificers.

The threatened punishment is deliberately humiliating in temple terms: God will spread the dung of their sacrifices on their faces. The offal of sacrificed animals was carried outside the camp to be burned, the most unclean waste in the system. It is the strongest possible way of saying their service had become garbage.

The second half turns to marriage, and it names a live crisis. Men were divorcing the wives of their youth and marrying "the daughter of a strange god" — women from the surrounding peoples who brought their gods with them. Ezra and Nehemiah both had to confront exactly this, and Nehemiah records children who could not even speak the language of Judah.

In a community of a few tens of thousands surrounded by larger populations, intermarriage was not only a religious risk but an identity one. The book's concern, though, is stated as covenant faithfulness: the LORD has been witness between you and the wife of your covenant.

The imagery is domestic and painful. They cover the altar with tears, weeping and crying out, wondering why God does not accept their offering — while the wives they discarded are the reason.

"Let none deal treacherously against the wife of his youth" is the sentence, and the reason given is that God made them one and "he sought a godly seed" — the children were the point.