When a single person marries a divorced person, the divorced person is committing adultery against the living spouse because the law of God said they are one flesh until they are dead - or - ones dies to loose them from the law. The single person would be married into fornication, because their spouse would belong to someone else so, to avoid fornication let every man have his own wife, and to have their own spouse the Word of God says that they can get divorced and to let that married person be reconciled back to their spouse, or remain unmarried.

( 1 Corinthians 7:11 ) But and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.

If we will go back to Adam again, God opened up his side and took out a rib, Then he closed it up instead thereof. Instead of what? Instead of putting the rib back into place he left it out and God created Adam a helpmate from the rib. This is now bone of my bone, flash of my flesh. When Eve got made at Adam and wanted to go, could she get back into the rib cage of Adam again? No! It was closed up instead thereof. When a man takes a woman as his wife, Spiritually speaking, God opens the side of man and puts the woman into the side of man and they become one flesh. What God has joined together, let not man put asunder. Man has not the ability to undo the work that only God can do. The man will have his rib in-tact until death breaks that Law of God, and the woman will be free to seek her another husband. But as long as they are both alive there is no divorce allowed by the word of God. When a single person marries a person who has a living spouse, and was married before, God gives the single person permission to cut loose that one who will never be one flesh with them. They are joined into the side of their spouse and the marriage is not valid in the eyes of God. That is why every scripture that pertains to married people always includes adultery when they separate and mix with another.

Because they are forever one flesh with the one whom they took the vow till death do us part. ( Hebrews 13:4 ) Marriage is honorable in all, and the bed undefiled: but whoremongers and adulterers God will judge.

We stand before God and make a vow before God and these witnesses “Till Death Do Us Part” That’s what God honors. He does not expect them to dishonor the vow they took before him, else they lied before God, and claim it was a mistake, and what God done was an error. If we make a vow to God, it will be required of us no matter the cost to us, in marriage or service to God, vows will be paid in full.

(Ecclesiastes 5:4-6 ) WE READ, When thou vowest a vow unto God, defer not to pay it; for he hath no pleasure in fools: pay that which thou hast vowed. 5 Better is it that thou shouldest not vow, than that thou shouldest vow and not pay. 6 Suffer not thy mouth to cause thy flesh to sin; neither say thou before the angel, that it was an error: wherefore should God be angry at thy voice, and destroy the work of thine hands?

In ROMANS 7:1-3 The Law has domion over a man as long as he is alive, and to show an example of that Law and it’s power over the man Paul tells them about the Law of marriage which also has the power over the people as long as they are alive.

(Rom 7:1-3) Know ye not, brethren, (for I speak to them that know the law,) how that