Read this profound statement about marriage from John Piper.
One of the reasons that I have emphasized the ultimate meaning of marriage so much in this series is that the meaning of marriage is such that human beings cannot legitimately break it. The ultimate meaning of marriage is the representation of the covenant keeping love between Christ and his church. To live this truth and to show this truth is what it means, most deeply, to be married. This is the ultimate reason why marriage exists. There are other reasons, but this is the main one. Therefore, if Christ ever abandons and discards his church, then a man may divorce his wife. And if the blood-bought church, under the new covenant, ever ceases to be the bride of Christ, then a wife may legitimately divorce her husband. But as long as Christ keeps his covenant with his bride, the church, and as long as the church, by the sustaining grace of God, remains the chosen people of Jesus Christ, then the very meaning of marriage will include: What God has joined, only God can separate, not man.
Do you see how this applies to our salvation?
If a person is truly a believer, then we cannot lose our salvation.
Christ does not divorce His Church and His Church may not divorce Christ.
Our marriages are pictures of Christ’s relationship to the church and thus divorce is not allowed unless we want our salvation to be dependent upon our own actions and not be dependent on the Lord’s Grace and Mercy to keep us.