In telling the story of Creation, the Torah relates that “G‑d finished on the seventh day His work which He had done, and He rested on the seventh day from all His work which He had done.”1

In commenting on the words “G‑d finished on the seventh day,” Rashi notes: “Rabbi Shimon says, ‘A human being can never be sure of the exact time, thus he must supplement the holy [day of Shabbos] by adding to it from the mundane [weekday]. G‑d, however, who knows His exact moments and seconds, can enter into it [Shabbos] by a hairbreadth.’ It thus seemed as if the work was concluded on that day.”

Rashi goes on to give another explanation: “What was the world lacking? Tranquillity. When Shabbos arrived, tranquillity came as well. The work was then concluded and complete.”

To indicate a tiny amount of space, the term “hairbreadth” is appropriate. However, a phrase like “the blink of an eye” seems more applicable when one is speaking about a minuscule unit of time. Why does Rashi use the former expression rather than the latter in explaining that G‑d labored on the seventh day for only “a hairbreadth”?

“A hairbreadth” describes something so inconsequential that it is not perceived in and of itself. A single strand of hair is so fine that it is almost invisible; it is only when many hairs are close together that they can readily be seen.

Rashi therefore uses the expression “a hairbreadth” to explain that G‑d’s “labor” on the seventh day cannot be construed as prohibited work. For when “everything was [already] done on the sixth day,”2 the labor done on the seventh was but “a hairbreadth,” i.e., were it not for the absolute completeness of the work done on the sixth day, the seventh day’s “labor” would not have been discerned at all. This is indeed “labor” that is permitted on Shabbos.

The following question, however, begs to be asked: Granted that labor of a mere “hairbreadth” is permitted on Shabbos, why was it necessary for G‑d to labor so long and hard that He entered even “a hairbreadth” into Shabbos; why not complete it all on the sixth day?

This was done in order to teach man a priceless lesson concerning the value of time: As long as an individual has the opportunity to fulfill the purpose for which he finds himself in this world, he is to do so to the best of his ability and until the last possible moment.

For “G‑d created nothing without a purpose.”3 Each and every thing which G‑d created — including every iota of time and space — has a purpose. If G‑d grants an individual a measure of time for the fulfillment of Torah study and the performance of mitzvos , and the person does not make full use of it, this unused time — be it only a twinkling — is considered wasted.

The preciousness of every moment is emphasized to an even greater degree by Rashi ’s additional question: “What was the world lacking ? Tranquillity. When Shabbos arrived, tranquillity came as well. The work was then concluded and complete.” Until the actual arrival of Shabbos and the concurrent “hairbreadth” of labor, all that had been achieved was considered “incomplete” and “lacking.”

This teaches us that using every moment wisely and well is so crucial that if an individual has occasion to do but another “hairbreadth” and wastes the opportunity, he is lacking completion in all those aspects of the work and service which he has fulfilled until then.

When all our moments, like G‑d’s, are so precious that none of them are wasted, when all are filled with positive accomplishments, then, like Him, we are able to enjoy the tranquillity that comes from knowing we did our best.

Based on Likkutei Sichos , Vol. V, pp. 24-34.