Does the sabbath rest law refer to a day or it is testifying of a Person? Does any of the law and the prophets speak and testify of anything but Christ?
The Law is a testimony of the Image and likeness of GOD. This Image and likeness was what we were created in. Christ came to reestablishment us to that image in Him through His Life, Death and Resurrection. Behold all things are new and of GOD!
Jesus has made it possible for us to live a Holy life in Him Through Him. This is the GOSPEL. This Gospel was the promise and intent that was purposed to Israel.
Let's take a closer look at Hebrews 4 again.
1) Let us therefore fear, lest, a promise being left us (the people of the writers day and us) of entering into his rest (the Gospel), any of you should seem to come short of it.
For unto us was the gospel (His Rest) preached, as well as unto them:
but the word preached did not profit them, not being mixed with faith in them that heard it. For we which have believed do enter into rest (His Rest; the Gospel), as he said, As I have sworn in my wrath, if they shall enter into my rest (the Gospel; the rest we have when Christ Jesus is our Life): although the works were finished from the foundation of the world. (the Gospel Rest has been available since Eden)
4)
For HE (GOD) spake in a certain place (the giving of the Commandments on Mt. Sinia) of the seventh day on this wise, And God did rest the seventh day from all his works.
5,6)
And in this place again, (GOD speaks of the Seventh Day) If they shall enter into my rest (the Gospel; the rest we have when Jesus is our life). Seeing therefore it remaineth that some must enter therein (the Gospel, and they to whom it was first preached entered not in (the Gospel) because of unbelief (obstinacy, obstinate opposition to the divine will):
If we receive the Gospel Rest in Christ GOD is calling us to the Word that HE spoke of the Seventh Day on Mt Sinia. The Gospel. Our rest in HIM and HE in us enables us now to partake of the Seventh Day Sabbath's hallowedness and truly rest physically from our physical Labors as GOD did from HIS on the Seventh Day Sabbath.
7) Again, he limiteth a certain day (a call to the Gospel Rest because
it remaineth that some must enter therein (the Gospel, and they to whom it was first preached entered not in (the Gospel) because of unbelief (obstinacy, obstinate opposition to the divine will ), saying in David, To day (Now), after so long a time; as it is said, To day (now) if ye will hear his voice, harden not your hearts.
Dabid's (beloved's) Word's though GOD where and are a call to repentance; GOD's Rest in Christ (the Gospel). For unto us was the Gospel (His Rest) preached,
as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it.
For (because of the word just shared in Psalm) if Jesus (Joshua leading them into Canaan) had given them rest (the Gospel Rest in Christ), then would he not afterward have spoken of another day (constant call to the Gospel because to whom it was first was preached did not profit them, not being mixed with faith in them that heard it ).
The leading them into the promise land was a symbol of what they already had available to them. After the forty years of roaming and seeing GOD's loving and guiding hand they were still only willing to receive the physical blessings and not the Spiritual; HIS Rest in Christ.
9) There remaineth (present tense) therefore a Sabbath keeping to the people of God.
This verse brings us back to verse 5, “And in this place again, (GOD speaks of the Seventh Day) If they shall enter into my rest (the Gospel; the rest we have when Jesus is our life).”
10) For he that is entered into his Rest (the Gospel), he also hath ceased from his own works,
as God did from his.
"As" is direct Comparison. There is no way around that. So it is A Ceasing from work like GOD did from HIS. It is the calling to those who entered in their rest (the Gospel rest in Jesus in GOD) to cease from their work AS GOD did.
GOD ceased from HIS PHYSICAL work on the Seventh Day. GOD is already and forever Spirit. So HE did not enter enter into any Spiritual rest as we do. He is our Spiritual rest. So we in harmony with Christ and the FATHER cease from our work on the Seventh Day as HE did. The Day HE hallowed (set apart) and blessed.
So what are our instructions in regards to keeping the Sabbath?
Because we have received the Gospel; the new heart and mind through Christ Jesus; old things having passed away, all things being new and of GOD. We Simply cease from our own works as GOD did from HIS. He simply rested from work; so we rest as HE did.
(Heb 4:1-10 KJV)