Albert Barnes Commentary Malachi 2:11

"Judah hath dealt treacherously, and an abomination is committed in Israel and in Jerusalem; for Judah hath profaned the holiness of Jehovah which he loveth, and hath married the daughter of a foreign god." — Malachi 2:11 (ASV)

Treacherously has Judah dealt; an abomination is committed in Israel - The prophet, by the order of the words, emphasizes the “treachery” and the “abomination.” This they have done: the very contrary to what was required of them as the people of God. He calls the remnant of Judah by the sacred name of the whole people, of whom they were the surviving representatives. The word “abomination” is a word belonging to the Hebrew and is used especially of things offensive to, or separating from, Almighty God: idolatry, as the central dereliction of God, and involving offences against the laws of nature, but also all other sins, such as adultery, which violate His most sacred laws and alienate from Him.

Has profaned the holiness of the Lord which He loved - This profanation was in themselves, who had been separated and set apart by God to Himself as a holy nation (Exodus 19:6); for Israel was holiness to the Lord (Jeremiah 2:3).

“The Lord is holy, perfect holiness; His name, holy; all things relating to Him, holy; His law, covenant, and all His ordinances and institutions holy; Israel, His special people, a holy people; the temple and all things in it consecrated to Him, holy; Jerusalem, the city of the great God, holy; indeed, the whole land of His inheritance, holy; so that whoever does not observe those due respects which belong to any of these, may be said to have profaned the holiness which He loved.”

Unlawful marriages and unlawful lusts were in themselves a special profanation of that holiness. The high priest was to take a virgin of his own people to wife, and not to profane his seed among the people (Leviticus 21:14–15). The priests who married strange wives, defiled the priesthood and the covenant of the priesthood (Nehemiah 13:29). The marriage with idolatresses brought, as one consequence, the profanation by their idolatries.

The prohibition is an anticipation of the fuller revelation in the Gospel that the body is the temple of the Holy Spirit, and so, that sins against the body are profanations of the temple of God (1 Corinthians 6:15–20).

“As those who acknowledge, worship, and serve the true God are called His sons and daughters (Deuteronomy 32:19; 2 Corinthians 6:18), so those who worshipped any strange god are, by like reason, here called the daughters of that god. Hence, the Jews say, ‘He who marries a pagan woman is, as if he made himself son-in-law to an idol.’”

Has married the daughter of a strange god - And so he came into the closest relation with idols and with devils.