In Parashat Chukat, Moshe and Bnei Yisrael are set to fight Og, king of Bashan, and his army. Hashem tells Moshe, “Al Tira Oto, Ki VeYadecha Natati Oto VeEt Kol Amo,” “Do not fear, for I have given him and his people into your hand” (VaYikra 21:34). But didn’t Moshe already know Hashem was on his side? What would scare Moshe even for a second that would make it necessary for Hashem to remind him He was on his side?
Rashi explains that Moshe was afraid to fight Og, because Og had informed Avraham in Parashat Lech Lecha that Lot had been captured by the four kings. Moshe feared Og’s merit for helping Avraham might cause Hashem to protect him. Hashem therefore reassures Moshe that He is on Bnei Yisrael’s side, and not Og’s.
Ramban challenges Rashi based on Rashi’s own comment in Lech Lecha. There, Rashi explains that Og's intentions were not to help Avraham, but rather to have him die in battle against the kings so that Og could marry Sarah. How, then, can Rashi assert here that Og has merit when he himself claimed earlier that Og has none? This is Ramban’s challenge to Rashi, and the reason why he does not accept Rashi’s explanation here.
The Chizkuni also explains what Moshe had to fear. He quotes a Gemara in Horayot (10b) which states that a person who studies Torah and observes Mitzvot, even not LiShmah, will nonetheless receive the reward. Even Balak, who offered 42 Korbanot with the purpose of cursing the Jews, was nonetheless rewarded for them, specifically by having Rut as a descendant. Therefore, the Chizkuni answers Ramban’s question by claiming that Moshe was afraid of the merit Og might have accrued despite his ulterior motives.
The Kli Yakar presents a simpler answer. No one, not even Moshe, can know another person’s intent when doing something. Therefore, Moshe could not possibly have known that Og’s intentions when he informed Avraham of Lot’s capture were evil. All Moshe knew was that Og aided Avraham, and such aid is typically rewarded. Therefore, Hashem told Moshe not to fear Og, because he has not earned any merit; his intentions were evil, and Bnei Yisrael will conquer him.
We can learn a very important lesson from the Kli Yakar. We can never know a person’s true intentions, whether they are good or evil. We must therefore make sure to view everyone in a fair light and let Hashem alone judge a person’s intentions.