“You are to hallow the day of rest.”
 Our word “holy day” or “holiday” is so called from the Hebrew word “Sabbath,” which properly means to rest, that is, to cease from work; hence our common expression for “stopping work” literally means “taking a holiday.”61  In the Old Testament, God set apart the seventh day, appointed it for rest, and commanded it to be kept holy above all other days. As far as outward observance is concerned, the commandment was given to the Jews alone. They were to refrain from hard work and to rest, so that both human beings and animals might be refreshed and not be exhausted by constant labor.  In time, however, the Jews interpreted this commandment too narrowly and grossly misused it. They slandered Christ and would not permit him to do the very same things they themselves did on that day, as we read in the gospel—as if the commandment could be fulfilled by refraining from work of any kind. This was not its intention, but rather, as we shall hear, it meant that we should sanctify the holy day or day of rest.
 Therefore, according to its outward meaning, this commandment does not concern us Christians. It is an entirely external matter, like the other regulations of the Old Testament associated with particular customs, persons, times, and places, from all of which we are now set free through Christ.65  But to give a Christian interpretation to the simple people of what God requires of us in this commandment, note that we do not observe holy days for the sake of intelligent and well-informed Christians, for they have no need of them. We observe them, first, because our bodies need them. Nature teaches and demands that the common people—menservants and maidservants who have gone about their work or trade all week long—should also retire for a day to rest and be refreshed.  Second and most important, we observe them so that people will have time and opportunity on such days of rest, which otherwise would not be available, to attend worship services, that is, so that they may assemble to hear and discuss God’s Word and then to offer praise, song, and prayer to God.
 But this, I say, is not restricted, as it was among the Jews, to a particular time so that it must be precisely this day or that, for in itself no one day is better than another. Actually, worship ought to take place daily. However, because this is more than the common people can do, at least one day a week ought to be set apart for it. Because Sunday has been appointed for this purpose from ancient times, it should not be changed, so that things may be done in an orderly fashion and no one create disorder by unnecessary innovation.
 This, then, is the simple meaning of this commandment: Because we observe holidays anyhow, we should use them to learn God’s Word. The real business of this day should be preaching for the benefit of young people and the poor common folk. However, the observance of rest should not be so restrictive as to forbid incidental and unavoidable work.
 Accordingly, when you are asked what “You are to hallow the day of rest” means, answer: “Hallowing the day of rest means to keep it holy.” What is meant by “keeping it holy”? Nothing else than devoting it to holy words, holy works, and holy living. The day itself does not need to be made holy, for it was created holy. But God wants it to be holy for you. So it becomes holy or unholy on your account, depending on whether you spend it doing something holy or unholy.  How does such sanctifying take place? Not when we sit behind the stove and refrain from hard work, or place a garland on our head and dress up in our best clothes, but, as has been said, when we make use of God’s Word and exercise ourselves in it.
 Truly, we Christians ought to make every day such a holy day and devote ourselves only to holy things, that is, to occupy ourselves daily with God’s Word and carry it in our hearts and on our lips. However, as we have said, because we all do not have the time and leisure, we must set aside several hours a week for the young people, or at least a day for the whole community, when we can concentrate only on these matters and deal especially with the Ten Commandments, the Creed, and the Lord’s Prayer, and thus regulate our entire life and being in accordance with God’s Word.  Whenever this practice is in force, a holy day is truly kept. When it is not, it ought not be called a Christian holy day. For non-Christians can spend a day in rest and idleness, too, and so can the whole swarm of clerics in our time who stand day after day in the church, singing and ringing bells, but without keeping a single day holy, because they neither preach nor practice God’s Word, but rather teach and live contrary to it.
 For the Word of God is the true holy object above all holy objects. Indeed, it is the only one we Christians know and have. Even if we had the bones of all the saints or all the holy and consecrated vestments gathered together in one pile, they would not help us in the least, for they are all dead things that cannot make anyone holy. But God’s Word is the treasure that makes everything holy. By it all the saints have themselves been made holy.  At whatever time God’s Word is taught, preached, heard, read, or pondered, there the person, the day, and the work is hallowed, not on account of the external work but on account of the Word that makes us all saints. Accordingly, I constantly repeat that all our life and work must be based on God’s Word if they are to be God-pleasing or holy. Where that happens the commandment is in force and is fulfilled.  Conversely, any conduct or work apart from God’s Word is unholy in the sight of God, no matter how splendid and brilliant it may appear, or even if it is altogether covered with holy relics, as are the so-called spiritual walks of life, which do not know God’s Word but seek holiness in their own works.
 Note, then, that the power and force of this commandment consists not in the resting but in the hallowing, so that this day may have its special holy function. Other work and business are really not designated holy activities unless the person doing them is first holy. In this case, however, a work must take place through which a person becomes holy. This work, as we have heard, takes place through God’s Word. Places, times, persons, and the entire outward order of worship have therefore been instituted and appointed in order that God’s Word may exert its power publicly.
 Because so much depends on God’s Word that no holy day is sanctified without it, we must realize that God wants this commandment to be kept strictly and will punish all who despise his Word and refuse to hear and learn it, especially at the times appointed.  Therefore this commandment is violated not only by those who grossly misuse and desecrate the holy day, like those who in their greed or frivolity neglect the hearing of God’s Word or lie around in taverns dead drunk like swine. It is also violated by that other crowd who listen to God’s Word as they would to any other entertainment, who only from force of habit go to hear the sermon and leave again with as little knowledge at the end of the year as at the beginning.  It used to be thought that Sunday had been properly observed if one went to Mass or listened to the Gospel being read; however, no one asked about God’s Word, and no one taught it either. Now that we have God’s Word, we still fail to eliminate this abuse, for we permit ourselves to be preached to and admonished, but we listen without serious concern.
 Remember, then, that you must be concerned not only about hearing the Word, but also about learning it and retaining it. Do not think that it is up to your discretion or that it is an unimportant matter. It is the commandment of God, who will require of you an accounting of how you have heard, learned, and honored his Word.
 In the same way those conceited spirits should also be punished who, after they have heard a sermon or two, become sick and tired of it and feel that they know it all and need no more instructors. This is precisely the sin that used to be numbered among the mortal sins and was called acidia—that is, laziness or weariness—a malignant, pernicious plague with which the devil bewitches and deceives many hearts so that he may take us by surprise and stealthily take the Word of God away again.
 Let me tell you this. Even though you know the Word perfectly and have already mastered everything, you are daily under the dominion of the devil, and he does not rest day or night in seeking to take you unawares and to kindle in your heart unbelief and wicked thoughts against these three and all the other commandments. Therefore you must constantly keep God’s Word in your heart, on your lips, and in your ears. For where the heart stands idle and the Word is not heard, the devil breaks in and does his damage before we realize it.  On the other hand, when we seriously ponder the Word, hear it, and put it to use, such is its power that it never departs without fruit. It always awakens new understanding, pleasure, and devotion, and it constantly creates clean hearts and minds. For this Word is not idle or dead, but effective and living.  Even if no other benefit or need drove us to the Word, yet everyone should be motivated by the realization that through the Word the devil is cast out and put to flight, this commandment is fulfilled, and God is more pleased than by any hypocrisy, no matter how brilliant.