Albert Barnes Commentary Malachi 2:15

"And did he not make one, although he had the residue of the Spirit? And wherefore one? He sought a godly seed. Therefore take heed to your spirit, and let none deal treacherously against the wife of his youth." — Malachi 2:15 (ASV)

And did not He – God, of whom he had spoken as the witness between man and his wife – “make one,” namely, Adam first, to mark the oneness of marriage and make it a law of nature, appointing “that out of man (created in His own image and likeness), woman should take her beginning, and, knitting them together, did teach that it should never be lawful to put asunder those, whom He by matrimony had made one?”

“Between those two, and consequently between all other married couples to be born from them, He willed that there should be one indivisible union. For Adam could be married to no other except Eve, since no other had been created by God, nor could Eve turn to any other man than Adam, since there was no other in the world.”

“‘Do not then infringe this sanction of God, and the unity of marriage, and do not degenerate from your first parents, Adam and Eve.’”

“If divorce had been good, Jesus says, God would not have made one man and one woman. Instead, having made one Adam, He would have made two women, if He had intended for him to cast out the one and bring in the other. But now, by the mode of creation, He established this law: that each should have, throughout, the wife whom he had from the beginning. This law is older than the one about divorce, just as Adam is older than Moses.”

Yet He had the residue of the spirit – (Genesis 2:7), “the breath of life, which He breathed into Adam, and man became a living soul.” All the souls that God would ever create are His, and He could have called them into being at once. Yet, in order to designate the unity of marriage, He willed to create only one. So our Lord argues against divorce (Matthew 19:4–6): “Have you not read, that He which made them at the beginning made them male and female?” They both together are called “one man” (Genesis 1:27) and, therefore, should also be of one mind and spirit, the unity of which they should faithfully preserve.

And why one? – “Seeking a seed of God,” that is, a seed worthy of God. For from a religious marriage, religious offspring are most to be hoped for from God; and by violating that law, those before the flood brought in a spurious, unsanctified generation, so that God in His displeasure destroyed them all.

“And take heed to your spirit,” which you too had from God, which was His, and which He willed in time to create. He closes, as he began, with an appeal to man’s natural feeling: “let none deal treacherously against the wife of his youth.”