Kommentar zu Bereschit 2:2

ויכל אלהים ביום השביעי AND ON THE SEVENTH DAY GOD FINISHED — R. Simeon says: A human being (literally, flesh and blood) who cannot know exactly his times and moments (who cannot accurately determine the point of time that marks the division between one period and that which follows it) must needs add from the week-day and observe it as the holy day (the Sabbath), but the Holy One, blessed be He, who knows His times and moments, began it (the seventh day) to a very hair’s breadth (with extreme exactness) and it therefore appeared as though He had completed His work on that very day (Genesis Rabbah 10:9). Another explanation: What did the world lack? Rest! Sabbath came — Rest came; and the work was thus finished and completed (Genesis Rabbah 10:9)!

ויכל אלוקים ביום השביעי, at the beginning of the seventh “day,” a moment which is indivisible from the time frame which follows, so that both the six previous “days” were an entity in themselves, and the seventh day was a totally self-contained entity. Our sages in Bereshit Rabbah 10,9 describe G’d as knowing the precise moment between the sixth and seventh day and describe it as “thin as a hair’s breadth.” [I believe the problem confronting the sages was the statement that G’d had completed all His work in the six days, and yet the Torah speaks of Him completing, ויכל, His work on the ”seventh” day, something that appears to be a contradiction to the former statement. Ed.]

ויכל אלוקים ביום השביעי. G'd completed on the seventh day. The plain meaning of the verse is to tell us that G'd did not engage in creational activities that the Torah has not mentioned after that date. The term כלה, completed, includes anything that had been in G'd's mind to do. It also means that G'd did not only desist from work on that Sabbath, but that He did not resume activity on the following six days.