Therefore God has also most richly blessed this estate [marriage] above all others, and, in addition, has bestowed on it and wrapped up in it everything in the world, to the end that this estate might be well and richly provided for. Married life is therefore no jest or presumption; but it is an excellent thing and a matter of divine seriousness. For it is of the highest importance to Him that persons be raised who may serve the world and promote the knowledge of God, godly living, and all virtues, to fight against wickedness and the devil.
Large Catechism, Sixth Commandment, 208