The true sabbath rest is resting in the finished work of Christ
Genesis 2:1 - Thus the heavens and the earth were FINISHED, and all the host of them.
 And on the seventh day God ended his work which he had made; and he RESTED on the seventh day from all his work which he had made.
 And God blessed the seventh day, and sanctified it: because that in it he had RESTED from all his work which God created and made.
John 19:30 - When Jesus therefore had received the vinegar, he said, IT IS FINISHED: and he bowed his head, and gave up the ghost.
Matthew 11:28 - Come unto me, all ye that labour and are heavy laden, and I will give you REST.
 Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find REST unto your souls.
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.
 For he spake in a certain place of the seventh day on this wise, And God did REST the seventh day from all his works.
 For he that is entered into his REST, he also hath ceased from his own works, as God did from his.
Romans 4:4 - Now to him that worketh is the reward not reckoned of grace, but of debt.
 But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
God created the world in 6 days and then He rested on the 7th day. He did this and commanded His people to do this in the old testament to foreshadow/show a type of what Jesus would do for us on the cross. We all know what Jesus did for us, He was born of a virgin, lived a sinless life, took our sins upon Himself, shed His blood on the cross and died for our sins, then rose from the grave. Well, on the cross He cried out, "It is finished!" and that meant that His work was finished. He did all He needed to do for us to be saved/jusified before God. Now by believing in Jesus and His finished work we can enter into His rest, we can stop trying to earn our way into Heaven, which is impossible to do anyway, and we can rest assured knowing that through faith in Jesus Christ and His finished work we are justified before God. Now Jesus says, "Come unto me, all ye that labour [trying to earn your way into Heaven] and are heavy laden [still burdened by your sins and the guilt and shame of them], and I will give you REST [assurance that your are justified before God through faith in Me]. Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find REST unto your souls. The work is done. You can't add anything to the finished work of Christ. Simply believe and rest.
Romans 5:1 - Therefore being justified by faith, we have peace with God through our Lord Jesus Christ:
 By whom also we have access by faith into this grace wherein we stand, and rejoice in hope of the glory of God.
 For when we were yet without strength, in due time Christ died for the ungodly.
 For scarcely for a righteous man will one die: yet peradventure for a good man some would even dare to die.
 But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us.
 Much more then, being now justified by his blood, we shall be saved from wrath through him.
 For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life.
 And not only so, but we also joy in God through our Lord Jesus Christ, by whom we have now received the atonement.