In regards to Hebrews 4:9, Sabbatismos is
only used once in the Bible and is properly translated "sabbath rest," yet in context in Hebrews 4, we can see the author of Hebrews is attaching to the sabbath a new and
expanded meaning beyond that of sabbaton, which is otherwise used to denote the weekly sabbath day under the law.
*Had the writer of Hebrews wanted to indicate the 7th day sabbath, he would have used sabbaton, the standard word for sabbath. But he didn't. The whole context is about rest, so sabbatismos must be understood as "sabbath rest" in an expanded meaning beyond that of sabbaton, as WE Vine's correctly points out.
Sabbath rest (4520) (sabbatismos from sabbatízo = keep the Sabbath) literally means a keeping of a sabbath or a keeping of days of rest.
It is used in this passage not in the literal sense (meaning to keep a specific day, the "Sabbath" day) but to describe a period of rest for God’s people which is modeled after and is a fulfillment of the traditional Sabbath.
SABBATISMOS a Sabbath-keeping, is used in Heb. 4:9, R.V., "a Sabbath rest," A.V. marg., "a keeping of a Sabbath" (akin to sabbatizoµ, to keep the Sabbath, used, e.g., in Ex. 16:30, not in the N.T.);
here the Sabbath-keeping is the perpetual Sabbath rest to be enjoyed uninterruptedly by believers in their fellowship with the Father and the Son, in contrast to the weekly Sabbath under the Law.
Hebrews 4:10 says the one who has entered His rest has himself also rested from his works, as God did from His. That person has entered in God’s rest through Jesus "rests from his own work" (in contrast with law keeping) as God ceased or rested from His works in the seventh day of Creation. God's ultimate, true rest did not come through Joshua or Moses, but through Jesus Christ. Joshua led Israel into the promised land, which was merely the earthly rest which was but a
shadow of what was involved in the heavenly rest. The rest in Christ that God offers is spiritual and is superior to that which Joshua obtained. Israel's earthly rest was filled with conflict and attacks from their enemies and the daily cycle of work. The "sabbatismos" rest enjoyed uninterruptedly by believers in their fellowship with the Father and the Son, in contrast to the weekly sabbath under the law, is found only in Christ and not Law keeping.
Although for centuries the Jews had found their physical rest in a day, the new covenant takes the focus off the shadows of the Old Testament signs and rituals and reveals their spiritual substance,
the fulfillment/reality—in the person of Jesus Christ. (Colossians 2:16-17) Christians find "sabbatismos" rest in Christ's finished work on the cross through faith in His death, burial and resurrection as the ALL-sufficient means of their salvation, which is what it means to "believe" the gospel. (Romans 1:16; 1 Corinthians 15:1-4) Rest for the Christian is entered into by ceasing from one’s "works" of trying to earn salvation though keeping the law, namely, "salvation by grace plus law, faith plus works." (Galatians 1:6-9) Paul explains that the Jewish holy days, including the weekly sabbath, were merely a “shadow” which pointed to Christ; therefore, Christians should not feel obligated to observe them once the "reality" has come. (Colossians 2.16-17)
For an Adventist to give up weekly sabbath keeping is essentially giving up salvation. They even teach the ludicrous doctrine that near the end of time the "mark of the best" of Revelation 14 will be placed upon those who worship on Sunday instead of Saturday.
Mark of the Beast
"Here we find the mark of the beast. The very act of changing the Sabbath into Sunday, on the part of the Catholic church, without any authority from the Bible." (Ellen G. White, The Mark of the Beast, page 23).
"The Sunday Sabbath is purely a child of the Papacy. It is the mark of the beast." (Advent Review, Vol. I, No. 2, August, 1850).
"The change of the Sabbath is the sign or mark of the authority of the Romish church.” ... “The keeping of the counterfeit Sabbath is the reception of the mark." (Ellen G. White, Great Controversy, Vol. 4, page 281).
Ellen White - "It means eternal salvation to keep the Sabbath holy unto the Lord. God says: "Them that honor Me I will honor." 1 Samuel 2:30. E.G. White, 6 Testimonies, pp. 353-356.
Ellen G White also claimed she had a vision in which she was shown the law of God in a heavenly sanctuary, and the fourth commandment (concerning the sabbath) was surrounded by a halo of light, then began to uphold sabbath-keeping as a primary doctrine.
Ellen G White: In the holiest I saw an ark; ... In the ark was the golden pot of manna, Aaron's rod that budded, and the tables of stone which folded together like a book. Jesus opened them, and I saw the ten commandments written on them with the finger of God. On one table were four, and on the other six. The four on the first table shone brighter than the other six. But the fourth, the Sabbath commandment, shone above them all; for the Sabbath was set apart to be kept in honor of God's holy name. The holy Sabbath looked glorious—a halo of glory was all around it. Early Writings of Ellen G. White, page 32, 33.
Ellen G White makes an idol of the sabbath commandment by saying that it shown brighter than the rest with a halo around it. The fact remains that the sabbath commandment from the old covenant for Israel was never included in the new covenant for Christians. It was a law given to the Israelites under the old covenant (Exodus 31:16-17; 35:1-3; Deuteronomy 5:1-15; Numbers 15:32-36; Nehemiah 9:13 etc..) and not to Christians under the new covenant. (Colossians 2:16-17)
Misguided teachers of the law are forced to interpret "sabbatismos" rest basically as sabbaton (keep the weekly sabbath day under the law) because they miss the expanded meaning from the context of Hebrews 4 and remain on the old covenant plantation of law. Reminds me of the Israelites in Romans 10:1-4.