"G‑d revealed Himself to [Abraham] in the Plains of Mamre, as he sat in the doorway of his tent in the heat of the day" (Genesis 18:1).

Our sages note that, "It was the third day following his circumcision (described in the closing verses of the previous parshah) and G‑d came to inquire after his health" (Talmud, Bava Metzia 86). But why did G‑d wait three full days to visit the ailing Abraham? G‑d's delay is even more puzzling in light of the fact that the natural healing process following circumcision takes three days (see Talmud and commentaries, Shabbat 134b). The Talmud (Nedarim 39b) also tells us that "one who visits a sick person removes 1/60th of his illness." If a human visit has such an effect, a divine visit would certainly have removed Abraham's illness entirely. Apparently, G‑d waited until a primary benefit of visiting the sick was no longer operative!

But that exactly was the point. The chassidic masters explain that the purpose of a mitzvah is to transform and sanctify the physical world. Thus, a mitzvah performed by miraculous means is invalid. Let's say that that it's Passover and I don't have any matzah, but I'm a holy man with the power to perform miracles. I wave my wand, and a stack of matzahs materializes on the table. Eating them would not fulfill the mitzvah of eating matzah on Passover, since the entire point of a mitzvah is to elevate the natural reality. For Abraham to have been miraculously cured of the natural results of the mitzvah of circumcision would have compromised the significance of his mitzvah.

In Abraham's case, we see this principle applied not only to the mitzvah itself, but to the entire swath it cuts through time and space. After all, as long as Abraham fulfilled the mitzvah of circumcision by natural means, why should it matter if one minute later all natural effects of his action would be miraculously whisked away? But everything connected with a mitzvah—everything that enables it and everything that results from it—shares in its transformative power, and becomes holier and more G‑dly in the process.

Therein lies an important lesson to each of us. Often we look at our lives and are disappointed by how little of it is directed towards a higher purpose. We would love to learn more, but can only spare a few minutes a day. We wish we could give more to charity, but are able to give just a small amount. In truth, however, every action extends backwards and forward in time and has a ripple effect in every area of our lives. We may have studied for just a few minutes, but a single new idea will affect our thinking throughout the day. We give a few dollars to charity, and the time and effort we expended to earn that money are "elevated" along with it. Like a small pebble cast into a pool, a single G‑dly deed will reverberate though our life and infuse it with purpose and meaning.