Verse 15. "And did not he make one?" - ONE of each kind, Adam and Eve.
Yet had he the residue of the Spirit, he could have made millions of pairs, and inspired them all with living souls. Then wherefore one? He made one pair from whom all the rest might proceed, that he might have a holy offspring; that children being a marked property of one man and one woman, proper care might be taken that they should be brought up in the discipline of the Lord. Perhaps the holy or godly seed, µyhla [rz zera Elohim, a seed of God, may refer to the MESSIAH. God would have the whole human race to spring from one pair, that Christ, springing from the same family, might in his sufferings taste death for every man; because he had that nature that was common to the whole human race. Had there been several heads of families in the beginning, Jesus must have been incarnated from each of those heads, else his death could have availed for those only who belonged to the family of which he was incarnated.
"Take heed to your spirit" - Scrutinize the motives which induce you to put away your wives.