Do not stand by the blood of your fellow.
… to see him dying, and you are able to save him; for example, if he is drowning in a river and a beast or thieves are approaching him.
Rashi’s commentary, ibid.
A cornerstone in the teachings of Rabbi Israel Baal Shem Tov, founder of the Chassidic movement, is the doctrine of hashgachah pratit, “specific divine providence.” Specific divine providence means that not only does G-d oversee and determine all that transpires in the universe, but that also every detail and every aspect of every event is by divine design. If a leaf is torn off its branch by a wind blowing in a distant forest, and is blown this way and that before coming to rest on a specific place—it is because it was so ordained by G-d toward a specific purpose.
The Baal Shem Tov also taught:
“From everything that a person sees or hears he is to derive a lesson in his service of G-d.”
These two principles are closely related; indeed, the second is a derivative of the first. If something happens, and you happen to witness or hear about it, then both the event and the fact that you have been made aware of it are by divine providence. The event could have taken place without your knowledge; so the fact that you have learned of it is also significant. It must prompt you to understand something or to do something, otherwise your awareness of it would have been to no purpose.
Therein lies the deeper meaning of the above-quoted passage from Rashi. Rashi explains the meaning of the verse “Do not stand by the blood of your fellow” by adding the words “to see him dying, and you are able to save him.” But the words “and you are able to save him” read more as statement of fact than a clause; it would seem that, for the sake of clarity, Rashi should have written “if you are able to save him” or “when you are able to save him.” In truth, however, the very fact that you see him dying should indicate to you that you are indeed able to save him. Rashi is saying: Do not hasten to conclude that there is nothing you can do about your brother’s distress. For if this were indeed the case, to what purpose would G-d cause you to witness it?
The Spiritual Dimension
Today, we are painfully aware that many of our brethren are threatened with spiritual extinction, G-d forbid. We see them drowning in materiality, we see them being devoured by a society that has lost its G-d and its moral moorings.
This awareness implies a duty and a responsibility: “Do not stand by the blood of your fellow” applies no less to spiritual dangers than to cases of physical jeopardy. It also carries a divine guarantee: the very fact that you have been made aware of your fellow’s plight means that you are capable of doing something about it.
Based on an address by the Rebbe, Shabbat Parshat Kedoshim 5746 (May 10, 1986)
Adapted from the teachings of the Rebbe by Yanki Tauber
 Likkutei Sichot, vol.XVI p.527