<<It…>>—<<Sabbath observance … did not cease when God entered into his rest after creation of this heaven and earth>>;
no, it started with God, when God after creation of this heaven and earth and after the fall man into sin, in and through the Son, had entered into His Own Rest “on the Seventh Day” and in and through the Son, “on the Seventh Day rested”. God by his Sabbath’s Institution of the Seventh Day, after the creation, “Rested” in the Son, while Adam and Eve had failed and disappointed God in His Own Rest. Sabbath observance did not cease, it began after we had entered upon our spiritual voyage to death without God and without Christ or hope. So <<Sabbath observance>> did not begin with us; it began with God.
Neither did Sabbath observance stop with us; it stopped with God in Christ in the death of death and sin <<on the cross>>.
<<Sabbath observance … did notcease with Joshua bringing the people into the promised land of rest>>,
Nor, ceased with “Jesus”, when He “gave the People of God Rest”—Himself—but began!
<<Sabbath observance … did not cease with David when he gave them rest from all the enemies around>>.
Therefore, would Sabbath observance end, “when JESUS, gave them Rest”—the Eternal Rest of Himself—“the Rest of God”? God forbid!
<<Sabbath observance … did not cease with the greater work of redemption by Christ as Christ set apart His Own Day.>>
No, when “JESUS AS GOD entered into His Own Rest”, when “JESUS AS GOD” had “finished ALL the works of God”— God’s works of His Redemption-Rest, Jesus with the first ever “Seventh Day Sabbath OF THE LORD GOD, from all his works RESTED”— rested with Eternal Rest in Full Fellowship of the Trinity and the redeemed first time, first day ever, "on the Sabbath".