NOTE: This is written from a Christian perspective, so I'm getting at the fundamental issue of the meaning and purpose of marriage, rather than the obvious financial, emotional and psychological harm divorce does to people.
The first 1e verses of Mark Chapter 10 (linked to above) were Friday's Gospel reading at Catholic masses. This reading tells of Jesus' teaching that marriage was ordained by God to be indissoluble. But why is that?
When you read the Bible, you frequently see marriage used to describe the relationship between man and God. Examples include: The Songs of Songs
which describes the love between an man and his beloved, some parts of Revelation
, and the book of Hosea
in which God has the prophet Hosea marry a prostitute in order to serve as an example of how God feels when the Israelites are unfaithful to him by worshipping other gods and disobeying his commands.
So what does this tell us about marriage? It's a sacrament: a visible sign of something sacred, something that draws us closer to God. It's meant to teach us about the relationship that we were meant to have with God and will again if we meet Him in Heaven after the end of our earthly existence. It's therefore a representation of God's love.
What do we know about God's love? One thing is: it's eternal. It never ends. So if God's love never ends, how can the symbol of that end be allowed to end?
What's something else we know about God's love? It's fecund, or fertile. After all, he not only has a Son ("begotten, not made") but the love between them is so powerful that it "took form" as the Holy Spirit. His love is so infinite that he created us in order to have still more people to love. How can a symbol of God's love not be fertile therefore? God's doesn't restrain the fertility of his love, how can we restrain the sacrament? (This doesn't exclude those who, for reasons beyond their control, are unable to have children from marriage, of course. They can still have an openness to life that reflects God's love.)
We also know that we are most happy when we fulfill God's plan, so if we enter into marriage with a proper view of what a great sacrament and gift it is, that's when we'll experience the most happiness. And even the msot happy marriage contains just a fraction of the happiness we'll experience when we're reunited with God in heaven.