Therefore this is an outstanding example of proper conduct. It confirms the injunction of St. Paul and teaches that servants should serve gladly because they are sure that, when they serve their masters faithfully either in their absence or in their presence, they are serving the Divine Majesty. And if we were not so blind and insane, we would thank God for the certain knowledge that we are serving God, not men, and that He so richly overwhelms us with good works and with His services. For whatever household tasks a servant performs in the house, even if he sweeps the house, he should be sure that he is performing this service for God.
But such is our foolishness that we think: “If I were able to serve the Lord God in heaven, then I would be willing to boast. These tasks are trivial and ordinary.” It is then that our flesh betrays itself; it does not believe it to be true that a servant who obeys his master is serving God—likewise a son, a daughter, a maid, or a pupil who obeys his teacher. For if we believe this, then all our works would be done with pride, joy, and gratitude. But because we do not have the Holy Spirit and do not believe that master, mistress, pastor, teacher, and the like are a divine ordinance, our obedience flags completely. Otherwise we would submit with joy.
If God were to order you with a new and unusual command to go for the purpose of bringing greetings to some friend or prince, you would do so with the utmost eagerness and without any delay. Why do you not do the same thing when your master or your parents give you an order? For God is giving you the same command and order through your master or parents, as Paul attests (Col. 3:24): “You are serving the Lord Christ.”
But who acknowledges or believes this? How much complaining there is in our day on the part of magistrates, masters, parents, and teachers! Men seem to be altogether frantic and to be driven by madness, yes, even filled with horrible murder. For children kill their parents—not with the sword; but through sadness of heart and sorrow they sap the strength of their parents, who are consumed by love and affection for their children, although they should be gladdened and refreshed by their children’s obedience. Domestics cause their masters to waste away solely because of the grief that is felt as the result of the insolence of the domestics. And thus all the lower classes grieve the Holy Spirit. This is worst, as is stated in the Epistle to the Hebrews (13:17): “Let them do this joyfully, and not sadly, for that would be of no advantage to you.”
Therefore examples of this kind should be carefully noted, in order that we may learn how important a matter it is faithfully to serve the masters who are set over us; for however contemptible and trivial our service or obedience may appear, they are nevertheless set over us by divine ordinance, whether in the household or in the government. But if you show the obedience you owe, you have a gracious God, a quiet heart, and a master who blesses you. If not, God is offended, and on account of your obstinate disobedience you cannot have a quiet conscience; you have lost the Lord God from your heart, a good conscience, and every blessing.
Luther’s works, vol. 4: Lectures on Genesis: Chapters 21-25 p 285-286