According to the text it references God finishing His creative work, resting on the seventh day: “So I swore in My wrath, ‘They shall not enter My rest,’ ” although the works were finished from the foundation of the world. 4 For He has spoken in a certain place of the seventh day in this way: “And God rested on the seventh day from all His works”; 5 and again in this place: “They shall not enter My rest.” God's works were finished since then. He was resting. But others did not enter into it. Those in the wilderness did not enter His rest. They did rest on the Sabbath, however, and this is a different rest.
Once again I respectfully disagree with your teachings here. Your argument here is that they rested on the Sabbath. My argument as already shown from the scriptures agree that they may have outwardly kept the Sabbath but they did not enter into Gods’ Sabbath rest that all those enter into through first believing and following Gods’ Word. As shown earlier God’s people in the wilderness did not enter into Gods’ rest because of their sins and unbelief. We do not enter into Gods’ rest unless we first believe and follow Gods’ Word (the gospel rest). Hebrews 4:3
For we which have believed do enter into rest, as he said, As I have sworn in my wrath, if they shall enter into my rest: although the works were finished from the foundation of the world.
The Plutarch reference is contested whether it is original to start with. And you didn't list the others.
Hebrews came before the other four uses referenced in the Anchor Bible dictionary. So is not dependent on these others. Two of the referenced in that work I do not have access to in the Greek, and you have not shown them. However, I did locate two of the references. One is in Justin Martry, and the other is in the Apostolic constitutions. Both are anarthrous as here.
Apostolic Constitutions
Book 2, 36
You shall observe the Sabbath, on account of Him who ceased from His work of creation, but ceased not from His work of providence: it is a sabbath rest for meditation of the law, not for idleness of the hands.
Here as in Hebrews it is describing the character of the rest, and is without the article.
Justin Martyr, ”Dialogue With Trypho” 23
Remain as you were born. For if before Abraham there was no need of circumcision, nor before Moses a sabbath rest, and feasts and sacrifices, neither now, after that, according to the will of God, Jesus Christ the Son of God has been born without sin, of a virgin sprung from the stock of Abraham.
Look a lot of these can be contested if you do not agree with them. So the only truthful reference at the end of the day is the bible. Anything outside of the bible of course is questionable even what you provide here. So what has been provided already to you are the biblical records of sabbatizo that is the verb form of sabbatismos and this clearly shows that it’s only use in the old testament Septuagint is to “sabbath keeping”.
As posted earlier The noun sabbatismos occurs only once in the Greek New Testament. It is derived from verb sabbatizo and was used in the Greek Septuagint to mean, “keep the Sabbath” (Exod. 16:30; Lev. 23:32; 26:34; 2 Chr. 36:21). The Catholic Church eventually came to prohibit “sabbatizing” (same Greek verb), which meant that they outlawed resting on the Sabbath. Bauer, Arndt, and Gingrich give the lexical definition for sabbatismos as “Sabbath observance” or the more metaphorical “Sabbath kind of rest.” The first definition comes from the way the word is actually used in early Greek literature.
Notice Gerhard Hasel’s summary of its usage: Hebrews 4:9 states, “There remains therefore a Sabbath rest for the people of God” The words “sabbath rest” translate the Gk noun sabbatismos, a unique word in the NT. This term appears also in Plutarch (Superst. 3 [Moralia 166a]) for sabbath observance, and in four post-canonical Christian writings which are not dependent on Hebrews 4:9 (Justin Dial. 23:3; Epiph. Panar. haer. 30, 2.2; Martyrdom of Peter and Paul, chap. 1; Const. Apost. 2.36.2) for seventh-day “sabbath celebration” (Hofius 1970: 103–5). (Gerhard Hasel, Anchor Bible Dictionary, vol. 5, p. 855)
The metaphorical sense, such as the secondary lexical definition of Bauer, Arndt, and Gingrich and the definition in Strong’s Concordance (“a sabbath keeping”), is a theological interpretion of the word rather than what it means in general use by Greek-speaking writers.
Each of the extra-biblical uses of the word in the Anchor Bible listing has to do with literal “sabbath keeping,” which meant resting on the Sabbath
Plutarch, De Superstitione 3.10
“O that our Greeks should found such barbarous rites, as tumbling in mire, rolling themselves in dunghills,
keeping of Sabbaths [sabbatismous] monstrous prostrations, long and obstinate sittings in a place, and vile and abject adorations . . .”
Justin, Dialogue with Trypho
23.3 [actually 15] “Do you see that the elements are not idle, and keep no Sabbaths? Remain as you were born. For if there was no need of circumcision before Abraham, or of the
observance of Sabbaths [sabbatismou], of feasts and sacrifices, before Moses; no more need is there of them now . . .”
Epiphanius, Panarion [“Medicine Chest”] Haereses 30.2.2
“For often in every Sect, when I reached the point, I have explained in connection with
Sabbath keeping [sabbatismou], circumcision and the rest, how the Lord has granted us something more perfect.”
Martyrdom of Peter and Paul, chap. 1
“And when thou seest Peter, contend against his teaching, because be has destroyed all the bulwarks of our law; for he has prevented the
keeping of Sabbaths [sabbatismos] and new moons, and the holidays appointed by the law. And Paul, answering, said to them: That I am a true Jew, by this you can prove; because also you have been able to keep the Sabbath, and to observe the true circumcision; for assuredly on the day of the Sabbath God rested from all His works. We have fathers, and patriarchs, and the law. What, then, does Peter preach in the kingdom of the Gentiles? But if he shall wish to bring in any new teaching, without any tumult, and envy, and trouble, send him word, that we may see, and in your presence I shall convict him. But if his teaching be true, supported by the book and testimony of the Hebrews, it becomes all of us to submit to him.
Apostolic Constitutions 2.36.2
“Thou shalt
observe the Sabbath [sabbatismos], on account of Him who ceased from His work of creation, but ceased not from His work of providence: it is a rest for meditation of the law, not for idleness of the hands.”
Whether pro-Sabbath observance or anti-Sabbath observance, the passages make it clear that
sabbatismos means “sabbath observance” and not just a “sabbath-like rest.”
Hope this is helpful