GOD SAID in Hebrews 10:1 "For the law having "a shadow of good things to come," and not the very image of the things..." tells us that GOD "commanded" the Israelites to "rest" on the Day of Sabbath under the Old Covenant (Exodus 34:21) but "was a shadow of things to come" under the New Covenant!
However, GOD made a New Covenant (Jeremiah 31:33) with "Better Promises" (Hebrews 8:6) under which "sacrifices (Sabbath) and offerings" HE has "no pleasure" (Hebrews 10:6)!
The Sabbath was given for "A" day" of "rest" under the Old Covenant but under the New Covenant, our "days of rest" never ends!
GOD SAID in Hebrews 4:11 "Let us therefore, labor to enter into that "rest" (Sabbath), lest any man fall after the sample of "unbelief."
GOD SAID in Colossians 2:16-17 "Let no man judge you...in respect of an holyday,...or of the Sabbath days: Which are "a shadow of things to come;" but the body is of Christ."
Did you notice the "s" on "days" in Colossians 2:16? Did you notice in verse 17 the Sabbath days were "a shadow of things to come" which is "the body of Christ?" Did HE not come? Did HE not make "Better Promises" (Hebrews 8:6) under the New Covenant?
GOD SAID in Hebrews 9-11 "But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building."
GOD SAID in Hebrews 4:9-11 of the Old Covenant's "rest" (aka Sabbath Day) that under the New Covenant which has "Better Promises;" "There remaineth therefore a "rest" to the people of GOD. For he that is entered into HIS "rest," he also hath ceased from "his own works," as GOD did from HIS. Let us labor therefore to enter into "THAT REST," lest any man fall after the same example of UNBELIEF."
Therefore, our "rest" (Sabbath Days) are EVERYDAY "IF" we BELIEVE and HAVE "FAITH" in HIS WORD (Psalm 23)!
GOD SAID "Let no man judge you in respect of the Sabbath "days" for under the New Covenant ANYDAY and EVERYDAY is "rest" (aka Sabbath Days) when we BELIEVE and rely TOTALLY on HIM and HIS "Better Promises" under the New Covenant!
In other words, "Give up self ("your works") and rely TOTALLY on GOD (aka WORD) to "enter into "THAT REST" (aka Sabbath)!
But how can one know of HIS "Better Promises" if they don't "STUDY" (II Timothy 2:15)?