When man lives outside of God's will there is never any peace. The Bible tells us that the guilty flee when no one is chasing them. When we come to our senses and come to God for forgiveness we find peace, we find that rest that God is speaking of. It's a rest where there is no more hiding from God. It's a rest where there is no condemnation or guilt.
Lets look at some of the thoughts that run through the context of Hebrews.
Hebrews 2:1-3 Therefore we must give the more earnest heed to the things we have heard, lest we drift away. For if the word spoken through angels proved steadfast, and every transgression and disobedience received a just reward, how shall we escape if we neglect so great a salvation, which at the first began to be spoken by the Lord, and was confirmed to us by those who heard Him,
Hebrews 3:5-19 And Moses indeed was faithful in all His house as a servant, for a testimony of those things which would be spoken afterward, but Christ as a Son over His own house, whose house we are if we hold fast the confidence and the rejoicing of the hope firm to the end. Therefore, as the Holy Spirit says: "Today, if you will hear His voice, do not harden your hearts as in the rebellion, in the day of trial in the wilderness, where your fathers tested Me, proved Me, and saw My works forty years. Therefore I was angry with that generation, and said, `They always go astray in their heart, and they have not known My ways.' So I swore in My wrath, `They shall not enter My rest.' Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God; but exhort one another daily, while it is called "Today,'' lest any of you be hardened through the deceitfulness of sin. For we have become partakers of Christ if we hold the beginning of our confidence steadfast to the end, while it is said: "Today, if you will hear His voice, do not harden your hearts as in the rebellion.'' For who, having heard, rebelled? Indeed, was it not all who came out of Egypt, led by Moses? Now with whom was He angry forty years? Was it not with those who sinned, whose corpses fell in the wilderness? And to whom did He swear that they would not enter His rest, but to those who did not obey? So we see that they could not enter in because of unbelief.
Hebrews 4:1-7 Therefore, since a promise remains of entering His rest, let us fear lest any of you seem to have come short of it. For indeed the gospel was preached to us as well as to them; but the word which they heard did not profit them, not being mixed with faith in those who heard it. For we who have believed do enter that rest, as He has said: "So I swore in My wrath, they shall not enter My rest,'' although the works were finished from the foundation of the world. 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''; and again in this place: "They shall not enter My rest.'' Since therefore it remains that some must enter it, and those to whom it was first preached did not enter because of disobedience, again He designates a certain day, saying in David, "Today,'' after such a long time, as it has been said: "Today, if you will hear His voice, do not harden your hearts.''
Hebrews 4:8-11 For if Joshua had given them rest, then He would not afterward have spoken of another day. There remains therefore a rest for the people of God. For he who has entered His rest has himself also ceased from his works as God did from His. Let us therefore be diligent to enter that rest, lest anyone fall after the same example of disobedience.
This rest we enter into is the rest that Christ provided. It's a finished work just like the finished work when God finished His creation work. We enter this rest through belief in the saving work of Christ but we remain in this rest by keeping our conscience clean before God and man. How we do that is by not hardening our hearts to the voice of God, by not neglecting so great a salvation, by exhorting one another daily, by keeping the commandments of God, by being mindful of sin's deceitfulness. When we continue in this we will remain in His rest.
All throughout the context of Hebrews we hear God referring to the times when His people were in the wilderness when they rebelled and did not listen to the voice of God. Instead they did just the opposite.
Lets go back to that time and see what God was dealing with.
Ezekiel 20:16 because they rejected My ordinances, and as for My statutes, they did not walk in them; they even profaned My sabbaths, for their heart continually went after their idols.
Ezekiel 20:18-21 "But I said to their children in the wilderness, `Do not walk in the statutes of your fathers, nor observe their judgments, nor defile yourselves with their idols. `I am the Lord your God: Walk in My statutes, keep My judgments, and do them; `hallow My Sabbaths, and they will be a sign between Me and you, that you may know that I am the Lord your God.' "Notwithstanding, the children rebelled against Me; they did not walk in My statutes, and were not careful to observe My judgments, `which, if a man does, he shall live by them'; but they profaned My Sabbaths. Then I said I would pour out My fury on them and fulfill My anger against them in the wilderness.
Ezekiel 20:23-24 "Also I lifted My hand in an oath to those in the wilderness, that I would scatter them among the Gentiles and disperse them throughout the countries, "because they had not executed My judgments, but had despised My statutes, profaned My Sabbaths, and their eyes were fixed on their fathers' idols.
Ezekiel 22:8 "You have despised My holy things and profaned My Sabbaths.
The people of God found blessing in the land of Canna, they found rest from their enemies yet that was not the rest God is speaking of. Even though they had a rest they still kept the Ten Commandments while in Canna. Jesus gives us a spiritual rest just like the physical rest they had in Canna but not to disobey the Ten Commandments. When we rest in Jesus we still have the Ten Commandments as our definition of love and rightousness that we must follow in order to remain in that rest.
Hebrews 4:13 Nothing in creation is hidden before God. To His eyes everything is naked and bare. We must give an answer to God.
Ecclesiaster 12:13-14Let us hear the conclusion of the whole matter: Fear God and keep His commandments, for this is the whole duty of man. For God will bring every work into judgment, including every secret thing, whether it is good or whether it is evil.
God is using the seventh day rest as a picture of how the work in Christ is finished and we can enter into the finished work. God is not saying the Sabbath is done away with, He is only using it to give us a picture of how the work in Christ in finished just like the work of creation was finished on the seventh day. The literal seventh day rest of the foruth commamdment is still there for the people of God but you can compare the finished work found in Christ with the finished work of creation.
It's kind of hard to explain, I hope this helped.
Blessings to you...