In Deuteronomy 5:15 God told the children of Israel to keep the Sabbath day because they had been slaves in Egypt and God had brought them out by a mighty hand and an outstretched arm. The Sabbath was a reminder that they had been slaves but were now free and it was God who had brought their deliverance about, it wasn’t their doing.
The Sabbath was symbolic of an important aspect of our salvation in the New Covenant. Just as the children of Israel were saved by God’s work and might not their own, so we have been saved from our sin and the slavery and judgment it held us under entirely by God, not any work or effort of our own. We are freely saved by grace.
The word Sabbath comes from a Hebrew verb meaning to cease or to stop. So on the Sabbath the people stopped, ceased work and rested. God’s salvation in the New Covenant brings us into what the book of Hebrews calls ” a rest “.
Hebrews 4:9-11 says:
9 There remains therefore a rest for the people of God. 10 For he who has entered His rest has himself also ceased from his works as God did from His.
Just as the children of Israel kept the Sabbath, entered a rest as a reminder that it was God who had saved them, we must live in a perpetual state of rest as Hebrews 4:10 says, ceasing from our own works because it is God who has saved us, not anything we have done, can do or will do! The weekly practice of resting in the Old Testament is fulfilled in us by a continuous practice of rest reflecting that our salvation and status as God’s children is something entirely brought about by God’s work not our own.
The children of Israel kept the Sabbath once a week, we keep it continually.