Pope Benedict XVI, then Cardinal Ratzinger, on the connection of sabbath and worship with creation:

The Bible, to be sure, could take up the fundamental notion of the universe as existing for the sake of worship, but at the same time it had to purify it. This idea is to be found there, as has already been said, in the context of the sabbath. The Bible declares that creation has its structure in the sabbath ordinace. But the sabbath is in its turn the summing up of Torah, the law of Israel. This means that worship has a moral aspect to it. God’s whole moral order has been taken up into it; only thus is it truly worship. To this must be added the fact that Torah, the law, is an expression of Israel’s history with God. It is an expression of the covenant, and the covenant is in turn an expression of God’s love, of his “yes” to the human being that he created, so that he could both love and receive love.[1. Joseph Ratzinger, ‘In the Beginning…’: A Catholic Understanding of the Story of Creation and the Fall, Ressourcement, trans. Boniface Ramsey, O.P. (Grand Rapids: Wm B. Eerdmans, 1995), 29.]