“I say these things in order that we may learn how honorable a thing it is to live in that estate which God has ordained. In it we find God’s word and good pleasure, by which all the works, conduct, and sufferings of that estate become holy, godly, and precious so that Solomon even congratulates such a man and says in Proverbs 5[:18], “Rejoice in the wife of your youth,” and again in Ecclesiastes 11 [9:9], “Enjoy life with the wife whom you love all the days of your vain life.” Doubtless, Solomon is not speaking here of carnal pleasure, since it is the Holy Spirit who speaks through him. He is rather offering godly comfort to those who find much drudgery in married life. This he does by way of defense against those who scoff at the divine ordinance and, like the pagans, seek but fail to find in marriage anything beyond a carnal and fleeting sensual pleasure.
Conversely, we learn how wretched is the spiritual estate of monks and nuns by its very nature, for it lacks the word and pleasure of God. All its works, conduct, and sufferings are un-Christian, vain, and pernicious, so that Christ even says to their warning in Matthew 15[:9], “In vain do they worship me according to the commandments of men.” There is therefore no comparison between a married woman who lives in faith and in the recognition of her estate, and a cloistered nun who lives in unbelief and in the presumptuousness of her ecclesiastical estate, just as God’s ways and man’s ways are beyond compare, as He says in Isaiah 55[:9], “As the heavens are higher than the earth, so are my ways higher than your ways.” It is a great blessing for one to have God’s word as his warrant, so that he can speak right up and say to God, “See, this thou hast spoken, it is thy good pleasure.” What does such a man care if it seems to be displeasing and ridiculous to the whole world?” (Luther’s Works, vol. 45, p.41-42).