This commandment, therefore, according to its gross sense, does not concern us Christians; for it is altogether an external matter, like other ordinances of the Old Testament, which were attached to particular customs, persons, times, and places, and now have been made free through Christ.
But to grasp a Christian meaning for the simple as to what God requires in this commandment, note that we keep holy days not for the sake of intelligent and learned Christians (for they have no need of it [holy days]), but first of all for bodily causes and necessities, which nature teaches and requires; for the common people, man-servants and maid-servants, who have been attending to their work and trade the whole week, that for a day they may retire in order to rest and be refreshed.
Secondly, and most especially, that on such day of rest (since we can get no other opportunity) freedom and time be taken to attend divine service, so that we come together to hear and treat of God's and then to praise God, to sing and pray.
However, this, I say, is not so restricted to any time, as with the Jews, that it must be just on this or that day; for in itself no one day is better than another; but this should indeed be done daily; however, since the masses cannot give such attendance, there must be at least one day in the week set apart. But since from of old Sunday [the Lord's Day] has been appointed for this purpose, we also should continue the same, in order that everything be done in harmonious order, and no one create disorder by unnecessary innovation.
Therefore this is the simple meaning of the commandment: since holidays are observed anyhow, such observance should be devoted to hearing God's Word, so that the special function of this day should be the ministry of the Word for the young and the mass of poor people, yet that the resting be not so strictly interpreted as to forbid any other incidental work that cannot be avoided.
Accordingly, when asked, What is meant by the commandment: Thou shalt sanctify the holy day? answer: To sanctify the holy day is the same as to keep it holy. But what is meant by keeping it holy? Nothing else than to be occupied in holy words, works, and life. For the day needs no sanctification for itself; for in itself it has been created holy [from the beginning of the creation it was sanctified by its Creator]. But God desires it to be holy to you. Therefore it becomes holy or unholy on your account, according as you are occupied on the same with things that are holy or unholy.
How, then, does such sanctification take place? Not in this manner, that [with folded hands] we sit behind the stove and do no rough [external] work, or deck ourselves with a wreath and put on our best clothes, but (as has been said) that we occupy ourselves with God's Word, and exercise ourselves therein.
And, indeed, we Christians ought always to keep such a holy day, and be occupied with nothing but holy things, i.e., daily be engaged upon God's Word, and carry it in our hearts and upon our lips. But (as has been said) since we do not at all times have leisure, we must devote several hours a week for the sake of the young, or at least a day for the sake of the entire multitude, to being concerned about this alone, and especially urge the Ten Commandments, the Creed, and the Lord's Prayer, and thus direct our whole life and being according to God's Word. At whatever time, then, this is being observed and practised, there a true holy day is being kept; otherwise it shall not be called a Christians' holy day. For, indeed, non-Christians can also cease from work and be idle, just as the entire swarm of our ecclesiastics, who stand daily in the churches, singing, and ringing bells but keeping no holy day holy, because they neither preach nor practises God's Word, but teach and live contrary to it.
For the Word of God is the sanctuary above all sanctuaries, yea, the only one which we Christians know and have. For though we had the bones of all the saints or all holy and consecrated garments upon a heap, still that would help us nothing; for all that is a dead thing which can sanctify nobody. But God's Word is the treasure which sanctifies everything, and by which even all the saints themselves were sanctified. At whatever hour then, God's Word is taught, preached, heard, read or meditated upon, there the person, day, and work are sanctified thereby, not because of the external work, but because of the Word which makes saints of us all. Therefore I constantly say that all our life and work must be ordered according to God's Word, if it is to be God-pleasing or holy. Where this is done, this commandment is in force and being fulfilled.
On the contrary, any observance or work that is practised without God's Word is unholy before God, no matter how brilliantly it may shine! even though it be covered with relics, such as the fictitious spiritual orders which know nothing of God's Word and seek holiness in their own works.
Note, therefore, that the force and power of this commandment lies not in the resting but in the sanctifying so that to this day belongs a special holy exercise. For other works and occupations are not properly called holy exercises, unless the man himself be first holy. But here a work is to be done by which man is himself made holy, which is done (as we have heard ) alone through God's Word. For this, then, fixed places, times, persons, and the entire external order of worship have been created and appointed, so that it may be publicly in operation.
Since, therefore, so much depends upon God's Word that without it no holy day can be sanctified, we must know that God insists upon a strict observance of this commandment, and will punish all who despise His Word and are not willing to hear and learn it, especially at the time appointed for the purpose.
Therefore not only those sin against this commandment who grossly misuse and desecrate the holy day, as those who on account of their greed or frivolity neglect to hear God's Word or lie in taverns and are dead drunk like swine; but also that other crowd, who listen to God's Word as to any other trifle, and only from custom come to preaching, and go away again, and at the end of the year know as little of it as at the beginning. For hitherto the opinion prevailed that you had properly hallowed Sunday when you had heard a mass or the Gospel read; but no one cared for God's Word, as also no one taught it. Now, while we have God's Word we nevertheless do not correct the abuse; we suffer ourselves to be preached to and admonished, but we listen without seriousness and care.
Know, therefore, that you must be concerned not only about hearing, but also about learning and retaining it in memory, and do not think that it is optional with you or of no great importance, but that it is God's commandment, who will require of you how you have heard, learned, and honored His Word.
Likewise those fastidious spirits are to be reproved who, when they have heard a sermon or two, find it tedious and dull, thinking that they know all that well enough, and need no more instruction. For just that is the sin which has been hitherto reckoned among mortal sins, and is called _achedia_, i.e., torpor or satiety, a malignant, dangerous plague with which the devil bewitches and deceives the hearts of many, that he may surprise us and secretly withdraw God's Word from us.
For let me tell you this, even though you know it perfectly and be already master in all things, still you are daily in the dominion of the devil, who ceases neither day nor night to steal unawares upon you, to kindle in your heart unbelief and wicked thoughts against the foregoing and all the commandments. Therefore you must always have God's Word in your heart, upon your lips, and in your ears. But where the heart is idle, and the Word does not sound, he breaks in and has done the damage before we are aware. On the other hand, such is the efficacy of the Word, whenever it is seriously contemplated heard, and used, that it is bound never to be without fruit, but always awakens new understanding, pleasure, and devoutness, and produces a pure heart and pure thoughts. For these words are not inoperative or dead, but creative, living words. And even though no other interest or necessity impel us, yet this ought to urge every one thereunto, because thereby the devil is put to flight and driven away, and, besides, this commandment is fulfilled, and [this exercise in the Word] is more pleasing to God than any work of hypocrisy, however brilliant.