Commentaries:
Here, Paul is relaying God's opposition to separation and divorce because they are obviously a result of a lack of peace. It is for this very reason that God hates divorce so much. Divorce creates not peace and unity but war and division. Among us, it should be a last resort.
Why? He tells us simply that we have been called to peace (verse 15). When we divorce, we are not making peace. We are actually going to war and causing separation. But God allows it, He says, in situations in which the relationship has been so undermined by sin (like adultery) that peace is impossible. Trust has been ruined. It takes quite a person to return to a loving relationship after such divisive, perfidious things have happened. It can be done, but He allows divorce because God considers peace more important.
So, the child of God must strive to do his or her part to make and maintain peace, especially in a marriage, even if the other spouse is an unbeliever. We should endeavor to make it work because that our election binds us to do just that. We have been called to be peacemakers, not to be disruptors, not to revel in conflict, but to make peace.
Richard T. Ritenbaugh
The Peacemakers
God has called us to peace. He expects us to keep His commandments, and in return He gives us peace of mind. "When a man's ways please the Lord, He makes even his enemies to be at peace with him" (Proverbs 16:7). Sin separates man from God, causing a confrontational relationship with Him whereby man receives His wrath. This is anything but peaceful! Peace leads to more peace, washing away strife and fear as a river sweeps away debris.
Martin G. Collins
Peace