Exodus 20:8-11 English Standard Version
8 “Remember the Sabbath day, to keep it holy. 9 Six days you shall labor, and do all your work, 10 but the seventh day is a Sabbath to the Lord your God. On it you shall not do any work, you, or your son, or your daughter, your male servant, or your female servant, or your livestock, or the sojourner who is within your gates. 11 For in six days the Lord made the heavens and the earth, the sea, and all that is in them, and rested on the seventh day. Therefore the Lord blessed the Sabbath day and made it holy.
This commandment was not the first time the Sabbath is mentioned in the scriptures.
Exodus 16:22-24 English Standard Version
22 On the sixth day they gathered twice as much bread, two omers each. And when all the leaders of the congregation came and told Moses, 23 he said to them, “This is what the Lord has commanded: ‘Tomorrow is a day of solemn rest, a holy Sabbath to the Lord; bake what you will bake and boil what you will boil, and all that is left over lay aside to be kept till the morning.’” 24 So they laid it aside till the morning, as Moses commanded them, and it did not stink, and there were no worms in it.
Exodus 16:31 Now the house of Israel called its name manna. It was like coriander seed, white, and the taste of it was like wafers made with honey.
The first connection between the Sabbath and work is related to the manna from heaven.
John 6:32-35 English Standard Version
32 Jesus then said to them, “Truly, truly, I say to you, it was not Moses who gave you the bread from heaven, but my Father gives you the true bread from heaven. 33 For the bread of God is he who comes down from heaven and gives life to the world.” 34 They said to him, “Sir, give us this bread always.” 35 Jesus said to them, “I am the bread of life; whoever comes to me shall not hunger, and whoever believes in me shall never thirst.
Considering that God made the Sabbath holy, can we keep it holy?