The Sabbath is for worship
Genesis 2 does not tell us much more about the significance of this seventh day. But as we learn more about it from Scripture we realize that the “rest” involved was not a lazy rest. Rather, it was intended to be a day when the working man could enjoy the Creator as well as the creation. He could devote himself more directly to fellowship with God and the worship of His Name. This “sabbath,” or “rest-day,” was a further special blessing which God gave to man so he would be refreshed and strengthened, encouraged and heartened by contemplating all that God had done and stimulated to worship God in response.
— Sinclair Ferguson, A Heart for God, p. 33