The Ohr Hachaim asks, what is the lesson of the words יִׁעיִׁבְשַה םוֹיַב תֹבְש יַו that the beginning of the possuk has not already told us.
The Medrash writes that there were creatures that Hashem was creating as it was getting dark on the sixth day. He did not end their creation when Shabbos arrived and He ceased from His work. He had created their essence but not their bodies, and that is how they exist.
This is difficult to understand. Hashem created everything with the words of His mouth; nothing took any time. How can it be said about Him that He did not have enough time to finish His handiwork?
The Torah is teaching us a great lesson with this fact. Hashem wished to teach us how important Shabbos is to Him. When a person has begun to work on a project and he must stop, it is more difficult for him than to push off the starting date. Once a person has begun a project, stopping in the middle means the loss of his previous work. He would not wish to move to a different job until he has finished the first.
When Shabbos arrived, not only did Hashem not start any new jobs, but He was even willing to have the loss of His previous work take place, to create a day of rest.
The Torah says וישבת – and He ceased. After He stopped and did not create anything else, He also ceased the work that He was doing. Even that which merely required finishing was ceased in honor of Shabbos.
This is the meaning of the words מכל מלאכתו – from all of His work. אשר עשה – that He did. Work that He was doing ceased in honor of Shabbos. This was not because of a lack of ability ch”v, as Hashem can do anything. This was to teach us the importance of Shabbos and how we should approach the Mitzvah of Shabbos. We must even stop that which we are in the middle of doing, in honor of the holy day.
