When...our natural reason...takes a look at married life, she turns up her nose and says, 'Alas, must I rock the baby, wash its diapers, make its bed, smell its stench, stay up nights with it, take care of it when it cries, heal its rashes and sores, and on top of that care for my wife, provide for her, labor at my trade, take care of this and take care of that, do this and do that, endure this and endure that, and whatever else of bitterness and drudgery married life involves? What, should I make such a prisoner of myself?
What then does Christian faith say to this? It opens its eyes, looks upon all these insignificant, distasteful, and despised duties in the Spirit, and is aware that they are all adorned with divine approval as with the costliest gold and jewels....I confess to thee that I am not worthy to rock the little babe or wash its diapers, or to be entrusted with the care of the child and its mother....O how gladly will I do so, though the duties should be even more insignificant and despised. Neither frost nor heat, neither drudgery nor labor, will distress or dissuade me, for I am certain that it is thus pleasing in [God's] sight.
From 'The Estate of Marriage', Luther's Works, by Martin Luther