Malachi 2:11 - Matthew Poole's English Annotations on the Holy Bible

Judah: though Judah only is named, yet the rest of the returned captives are included. Dealt treacherously: see Zechariah 2:10. An abomination; such treachery is a very abominable thing, God and all good men abhor it, and yet here it is committed in Israel, who are God's peculiar people, and above others should have been holy. And in Jerusalem; under the eye of the governors, the high priest and sanhedrim, nay, under the eye of God, who dwelt at Jerusalem; this could not but greatly provoke God. Profaned the holiness of the Lord: profanely violated the necessary cautionary law of marriage, confining Israel to marry within themselves, and not to endanger themselves and religion by joining affinity with idolaters, who would draw them and their children from the holy law, worship, and temple of God, which are the holiness that he loved. Which he loved; which he, i.e. Judah, once loved; so it was apostacy in Judah. Or which he, i.e. the Lord, loved above all; so it is a neglect of a main duty, it is slighting what God so greatly loved. And hath married the daughter of a strange god: Ezra 9:1, Ezra 10:2, mentions what nations they were whose daughters were by these Jews taken for wives, they were idolatrous nations, and the women were idolatresses when the Jews did marry them. This was bad; but these Jews had wives before, and they cast them off, or else took in these strangers and despised their former wives: this is the treachery and abomination that is here committed.