Geerhardus Vos, Biblical Theology (Edinburgh, 2015), 142.
In the beginning, when God finished creating the world, he rested on the seventh day. This is the Sabbath (more precisely pronounced "Shabbat"), which is the Hebrew word for “rest.”
In the OT, the Sabbath was the weekly remembrance not only of God’s creative work (Exod 20:11), but his redeeming work (Deut 5:15).
Genesis and Exodus were remembered every Sabbath.
Both creation and redemption coalesce in Jesus. Having finished all his work of redeeming the world, having completed his re-creation of humanity, he rested in the tomb of death on the seventh day. “It is finished,” he said.
His work was finished. So he took his rest. This was his Sabbath.
And it is a Sabbath with no conclusion. His resurrection ushers us into the Sabbath that creation has been awaiting since Genesis. We who are weak and heavy laden come to Jesus, and he Sabbaths us in himself. "Come to me, all you who labor and are heavy laden, and I will give you rest." I will Sabbath you in myself.
Today, Holy Saturday, Jesus takes a Sabbath in the tomb. And we who have been co-crucified with him rest there also, awaiting Easter Day and our co-resurrection.