“By the seventh day God had finished the work he had been doing; so on the seventh day he rested from all his work.”
The declarations about a Sabbath at creation contain on of the most remarkable and daring testimonies in the entire Pentateuch. In reading these statements, which move, to be sure, at that extreme limit of the protological, one must once again remember especially that they too derive completely from Israel’s position before God as it was constituted by the covenantal relation.
But what sense can there be in mentioning one further matter above and beyond the creation of the entire cosmos and all living creatures? And this matter is obviously of such significance that it is ranked above all the rest, and forms the final conclusion of the whole. That Babylonian creation epic also contains a concluding act following the work of creation; it is the public glorification of the god Marduk, in the assembly of the gods, as the chief gods name his fit names and extol him. How different, how much profound, os the impressive rest of Israel’s God!
This rest is in every respect a new thing along with the process of creation, not simply the negative sign of its end; it is anything but an appendix. Furthermore, it is significant that God “completed” his work on the seventh day (and not, as seems more logical, on the sixth – so the LXX![i. e. the Septuagint] ). This “completion” and this rest must be considered as a matter for itself. One should be careful about speaking of the “institution of the Sabbath”, as is often done. Of that nothing at all is said here. The sabbath as a cultic institution is quite outside the preview.
The text speaks, rather, of a rest that existed before man and still exist without man’s perceiving it. The declaration mounts, as it were, to the place of God himself and testifies that with the living God there is rest. But this word about rest is not at all speculative; it speaks of one facet of God which is turned to the world. Its first testimony is negative, but important enough: that the world is no longer in process of being created. It was not and is not incomplete, but it has been “completed” by God. (From G. von Rad, Genesis. A commentary, 1973, pp. 61-62)
I don’t agree that the the rest’s mention has not a cultic value, because the creation’s account follows the week’s scheme of seven days. And this is a cultic scheme, with the Sabbath at the end as the completion of the entire human and divine work. Scholars say that this account dates at the VI century BCE, during and even after the Babylonian exile, when the Hebrews begun to respect the Sabbath’s institution.