A Brief Discussion as to Why We Keep the Sabbath Day
The moral law, as written out in the Decalogue (the Ten Commandments), was implicitly given to man at the time of the covenant of works made to Adam (Gen 2:16-17), and Adam broke it when he sinned at the fall. God set up a statute for him to obey, but obedience to a statute implies there is moral authority behind the statute. Adam's sin wasn't really just eating of the forbidden tree – that was just a symptom of his sin: his sin was breaking the moral law in making himself as god before God in going against his Sovereign, coveting, etc. The same with Cain when he murdered: he was condemned for breaking the law, when there's no evidence of a direct statute from God to not murder (although there might have been). The point is the moral law was in place from the beginning. The keeping of a Sabbath day was part of this moral law from the beginning as evidenced by the 4th commandment given at Sinai to “remember the Sabbath day to keep it holy” – not to start keeping one, which was started by God earlier, before the fall (Gen 2:3), and which was kept by Israel before Sinai (Ex 16:23). The moral law was codified at Sinai for various reasons, among those being 1) it being written on tables of stone as type or shadow of it being written on the hearts of His people (Ez 11:19, 36:26; Jer 31:33); 2) the tablets being put in the ark, a type of Christ, evidencing He is the law and the keeper of it; 3) God explicitly granting His “chosen” (Israel as a type of spiritual Israel, in this instance – a specific people) light in declaring the law openly to them, so they would more clearly have the mind of God available to them, which a true believer wants to obey (Rom 7:15); etc. The moral law is perpetual (Matt 5:18).
Christ fulfilled the law perfectly, which evidenced His righteousness, which is the righteousness that is imputed to the elect, those over whom He is federal head (Rom 5:18) – His righteousness being the only way they can stand before God. Christ is not federal head of everyone that ever existed; otherwise, His righteousness would have been imputed to everyone, as their representative, and everyone would be saved, which we know is false. If Christ was federal head of everyone who ever existed, and His righteousness was not imputed to them, then God broke His end of the covenant, and Christ's righteousness failed. Further, Christ did not do away with the law (Matt 5:17); and under grace, is the law to be ignored that grace may abound? God forbid (Rom 6:1-2). Believers are created for good works (Eph 2:10), which is obedience to God out of love for Him (1 Jn 5:3). What are His commandments but keeping the moral law (not perfectly), which are (generally) to love God and your neighbor, as defined (generally) by the Decalogue? Again, a believer desires to keep the law – not that there is any righteousness in that, and moreover is filthy rags (Is 64:6). These works are only acceptable to God 1) because of Christ and His righteousness; and 2) when coming from faith (Heb 11:6), which is a gift (Eph 2:8), and not sprouted from within man by man – it is a work of God (Jn 6:29).
Since the Sabbath was shown to be part of the moral law at Sinai, part of loving God by keeping His commandments is keeping the Sabbath. While Christ is on whom we rest alone for righteousness, and who is our eternal Sabbath, there is no evidence in the Bible that these truths, or Christ perfectly keeping the law, removed this part of the moral law. Did Christ perfectly keeping the law remove the commandment to have no other gods before God? Or now allow me to kill my neighbor?
Christ kept the Sabbath, but defined it properly in what the Jews considered His breaking of the Sabbath – Matt 12:1-8; Mk 2:23-28. Here Christ in no way acknowledges He was breaking the Sabbath, and condemns His enemies for their defining of the Sabbath (in their legalistic traditions which missed the weightier matters of the law) when He alone is sovereign over it.
Further, non-Jew proselytes were encouraged to keep the Sabbath in Is 56:3-7.
Finally, some say Col 2:16 removes the keeping of the Sabbath day; but here the “Sabbath” word is plural and is listed amongst other ceremonial laws, which indicates it is referring to ceremonial Sabbaths (jubilee, etc.). Rom 14:5-6 also regards Jewish holy, or ceremonial, days. Or it could be argued it refers to keeping a Sabbath day differently, in not observing the detailed rudiments of the Jewish Sabbath (like traveling only small distances), or observing a Lord's Day Sabbath instead of the seventh day Jewish one.