from The Superstition of Divorce

It is not hard to see why the vow made most freely is the vow kept most firmly. There are attached to it, by the nature of things, consequences so tremendous that no contract can offer any comparison. There is no contract, unless it be that said to be signed in blood, that can call spirits from the vasty deep; or bring cherubs (or goblins) to inhabit a small modern villa. There is no stroke of the pen which creates real bodies and souls, or makes the characters in a novel come to life. The institution that puzzles intellectuals so much can be explained by the mere material fact (perceptible even to intellectuals) that children are, generally speaking, younger than their parents. “Till death do us part” is not an irrational formula, for those will almost certainly die before they see more than half of the amazing (or alarming) thing they have done.
~ G.K. Chesterton: Collected Works, Volume IV, pp. 237-238