If God has joined two people together in marriage, then only God can decide when that union is to be broken. He has told us in his Word that the marriage union is broken by death (see Romans 7:1–3; 1 Corinthians 7:39).

There are two motivations for why as Christians we must be eager to honour our marriage vows:

1. God has joined you to your spouse. God is sovereign and if he has joined you in marriage to your husband or wife, you can know that your marriage is a marriage that God has ordained. This does not make marriage easy, particularly if we had an arranged marriage or if we find it difficult living with our spouse. However, if we remember that the God who is sovereign is also the God who loves us, we can trust him to care for us and be concerned about us.
   As proof of this, consider the fact that Jesus’ teaching on marriage is part of this middle section of Mark’s Gospel where he is busy talking about what discipleship means. Jesus is on the way to the cross where he will suffer and die for the sake of his people (Mark 8:31; Mark 9:31; Mark 10:33–34). He is on the way to the cross where he will give his life in order to save a people who have turned their back on him and abandoned him. He is on his way to win a bride for himself, a bride who is unfaithful, who wants nothing to do with him. But through his suffering, through his death and by his Spirit, he is going to change his bride. He’s going to make her holy, win her freedom, and make her lovely (Ephesians 5:25–30).
   This should encourage us to know that Jesus Christ truly loves us. He has loved us so much that he was willing to suffer and die for us. We know that he is good, that he wants what is best for us. And if we can trust him with our salvation, we can surely also trust him with the most personal aspects of our life.
   You can be assured that God has given you all the resources you need to love and serve even in the most difficult of circumstances. Now it is certainly true that no marriage can be saved where only one person seeks to honour Christ. It takes two. If your husband or wife is not interested in following Jesus, not interested in changing and repenting where need be, not interested in forgiving and forgetting as God expects, then there will come a time when he or she decides to leave.
   But if both parties are eager to listen to Jesus because they’re motivated and encouraged by God’s love for them, then there is great hope. Indeed, for all married couples, God has promised help and support. God hates divorce (Malachi 2:16); he wants those whom he has joined together to stay together.

2. Marriage is meant to be an image of Christ’s relationship with his church. In Ephesians 5:32 Paul reminds us that marriage is a profound mystery because it is an image of Christ’s relationship with his church. He has loved his church with a love that endures forever, that does not change on account of human sin, that makes the church beautiful. He has also united himself with his church such that he is the head of the body. By his Spirit he lives in us (2 Corinthians 13:5; Ephesians 3:17) and we are found in him (Romans 6:5; Philippians 3:8–9).
   Our union with Christ is therefore the basis of our union with our spouse. Jesus Christ has loved us with an unconditional love that never ends; now we must love and serve one another, including our spouse. This is part of what it means for us to take up our cross, deny ourselves and follow Jesus. If God has joined us together in marriage, then we must not separate, we must do what we can to honour our marriage vows.