First of all, your brother is right in saying that “Saturday is the true sabbath and 7th day of the week.” God made this clear from the very beginning in Genesis 2:2-3, “And on the SEVENTH DAY God ended His work which He had done and He RESTED on the seventh day from all His work which He had done. Then God blessed the seventh day and sanctified it, because in it He RESTED from all His work which God had created and made” (NKJV). The word “sabbath” means “rest” and thus God “rested” on the seventh day and “sanctified it” (set it apart as a special day to observe).  Later, when God chose the nation of Israel to serve Him and to testify of Him before the nations, He commanded them to “keep the Sabbath” as a day where they too would “rest from their labors” and devote the day to worshiping Him. When God gave Israel the Law (the Ten Commandments) He said, “Remember the Sabbath Day, to keep it holy. Six days you shall labor and do all your work, but on THE SEVENTH DAY IS THE SABBATH of the LORD your God. In it you shall do no work: you, nor your son, nor your daughter, nor your male servant, nor your female servant, nor your cattle, nor your stranger who is within your gates. For in six days the LORD made the heavens and the earth, the sea, and all that is in them, and RESTED THE SEVENTH DAY. Therefore, the LORD blessed the Sabbath day and hallowed it” (Exodus 20:8-11).

I would suggest that you tell your brother, based on these passages, that he is absolutely correct regarding the Sabbath being Saturday, the seventh day of the week. Then I would point out that the Law (the “Ten Commandments”) was given specifically to the nation of Israel and that we never read of the Gentiles (all other nations) being given the Law, nor do we read of God giving the Law to the Church of God. Before we read verses to support this truth, I want to quote 1st Corinthians 10:32, “Give no offense, either to the Jews or to the Greeks or to the church of God.” Here we see these THREE CLASSES of mankind. The “Jews” are the nation of Israel; the “Greeks” are the Gentile nations; and the “church of God” is comprised of all believers in the Lord Jesus Christ. Whenever we read a portion of Scripture, we need to ask ourselves, “Which of these three classes is God speaking to?” We have already seen God speaking to the Jews when He gave them the Ten Commandments. Did God ever speak directly to the Gentiles or to the Church, commanding them to keep the Law, including the Sabbath Day? You can tell your brother that he will search in vain for even one verse where God commanded the Gentiles or the Church to “Remember the Sabbath Day, to keep it holy.” The fact is Scripture teaches us the opposite. Listen to the apostle Paul’s words regarding Gentiles and the Law in Romans 2:14, “For when Gentiles, WHO DO NOT HAVE THE LAW, by nature do the things in the law, these, ALTHOUGH NOT HAVING THE LAW, are a law to themselves.” In the next chapter Paul specifically singles out the Jews in saying, “Now we know that whatever the law says, it says TO THOSE WHO ARE UNDER THE LAW.” Later, in Romans 6:14 Paul spoke directly to the Church of God and he said, “For sin shall not have dominion over you, for YOU ARE NOT UNDER LAW but under grace.” Is this not clear? The Law was never given to the Gentiles nor was it given to the Church of God.

Hopefully these passages will help your brother to see that believers in Christ, who make up the Church of God, are “not under the Law.” If he does see this, he will see that it is wrong to “Remember the Sabbath Day, to keep it holy.” He may very well turn and ask you, “So, is there no special day set aside to rest from our labors and to worship God?” You can then point him to scriptures which teach us that the early church came together on the “FIRST DAY of the week” (which is Sunday) in order to worship the Savior in the breaking of bread. We read of this in Acts 20:7, “Now on the FIRST DAY of the week, when the disciples came together to break bread,” It was on the FIRST DAY of the week that the Lord Jesus rose victoriously from the dead (see Matthew 28:1-6; Mark 16:1-6 and Luke 24:1-6) and thus it was the FIRST DAY of the week that they celebrated His victory over Satan, sin and death.

If your brother does NOT see this truth and proceeds to judge you for NOT “keeping the Sabbath,” you can point him to Colossians 2:16-17 which says, “So let no one judge you in food or in drink, or regarding a festival or a new moon or SABBATHS, which are a shadow of things to come, but the substance is of Christ.” You can tell him that the Law, with its feast days and sabbaths, were meant to FORESHADOW the coming of Christ and the work He would accomplish on the cross. Every animal that was sacrificed on Jewish altars pointed to Jesus, the Lamb of God, who would put away sin by the sacrifice of Himself (see John 1:29 and Hebrews 9:26; 10:1-14). The Sabbath was a picture of the REST (from their sins!) Christ gives to every believer who trusts in Him and His finished work on the cross (see Matthew 11:28). Hopefully this would prevent him from judging you and could also serve to show him that the Law was only in force UNTIL Christ came (see Galatians 3:19-26 and 4:1-7).  (469.5)  (DO)