We have been taken out of the spiritual "house of bondage." We can see here that the Sabbath is enjoined on God's people for two basic reasons. The one reminds us that He is Creator. The other reminds us that, at one time, we were slaves.
Ezekiel 20 clearly demonstrates that when God's people do not keep the Sabbath, they lose their liberty. They go into captivity—for us, that means back to the captivity of Satan, the world, and sin. The Sabbath is given by God to keep His people free! It is the day to keep His people from going back into bondage.
God has specifically used the Sabbath throughout Israel's history as the day in which He emphasizes the Sabbath's tie to deliverance, liberty, to keeping His people free. On this day, He has pointedly performed acts of liberation for His people. For example, on what day did the children of Israel leave Egypt, the house of bondage? They left on an annual Sabbath, the first day of Unleavened Bread. On which day did they completely break free of their captors? It was on the following Sabbath, the seventh day of Unleavened Bread that they went through the Red Sea, were baptized, and went out into the wilderness. At that point, they were politically free.
On which day did God give His law? On the day of Pentecost, another Sabbath, which "if a man will keep, he will live in it." On which day did Israel go into the Promised Land? On a Sabbath day. On which day did the walls of Jericho come down? They came down on a Sabbath, and Israel made their first important conquest in the land.
This Sabbath redemption is all through the Old Testament. God did that to focus our minds on what the Sabbath is for. It is the day He has blessed for the purpose of liberation. It is the day He has blessed to continue the liberty of His people. Jesus also emphasized this in His ministry, driving this point home by how He used the Sabbath, giving us an example so that we could see how He wants us to use the Sabbath to the greatest benefit.