The Sabbath was a weekly celebration of God's work in Creation. God created in six days and rested on the seventh. He then commanded that every seventh day people cease from all normal activity and rest. In this respect, the Sabbath was a memorial of what had happened. But it was also a shadow of what was to come: the rest that would one day come from the work of Messiah.
Yeshua ha Mashiach has now done all of the work necessary for our Salvation. Our Salvation is not only based entirely upon God's grace (Ephesians 2:8-9) it is also based upon the finished work of Messiah. The work of Salvation is now done, therefore, we rest in Messiah.
"Come to me, all you who are weary and burdened, and I will give you rest. 29 Take my yoke upon you and learn from me, for I am gentle and humble in heart, and you will find rest for your souls. 30 For my yoke is easy and my burden is light" (Matthew 11:28-30, NIV).
or as The Message puts it;
"Are you tired? Worn out? Burned out on religion? Come to me. Get away with me and you’ll recover your life. I’ll show you how to take a real rest. Walk with me and work with me—watch how I do it. Learn the unforced rhythms of grace. I won’t lay anything heavy or ill-fitting on you. Keep company with me and you’ll learn to live freely and lightly."