Moshe hitting rock

From Daniel Lifshitz:

The latter portion of Parshat Chukat discusses Jews’ victory over the Amorite king Sichon, whose capital city was Cheshbon. The Torah tells us that Cheshbon was originally a Moabite city, but that it had been captured by Sichon along with a large portion of other Moabite territory. There is a famous midrash on this passage based on the fact that the word “moshlim” can also mean “ruler” and the name “Cheshbon” also means “accounting.” The midrash says “Those who are rulers (moshlim) over their evil inclination would say ‘Come and take an accounting (Cheshbon)’ – take an accounting of your deeds; think about what you gain from good deeds and what you lose as a result of bad deeds.” Very often, a midrash is not merely a homiletical tangent, but has a close connection with some aspect of the text. What is the connection between Sichon’s conquest of Moab and the battle against the evil inclination?

R’ Yonatan Eibeschutz (cited in Talelei Orot) provides a beautiful explanation. Cheshbon was a city on the border between the land of the Amorites and the land of the Moabites. It was not a particularly important city, and therefore the king of Moab did not focus resources on its defense. As a result, Sichon was able to conquer it. This was a fatal error by Moab, for once Sichon had established this beachhead, he was easily able to capture a much larger swath of Moabite territory. This is a metaphor for the battle against the evil inclination, which often tempts a person to violate a small mitzvah, since such an infraction is easier to rationalize than something more serious. Once a person gives in on something small, his defenses have been breached and each subsequent conquest becomes much easier for the evil inclination. By the same token, each victory over temptation, no matter how small, gives an individual a huge advantage in his future battles. Thus, the moshlim teach us “Come to Cheshbon” – do not repeat the mistake that the king of Moab made in his defense of Cheshbon; hold the frontline against the evil inclination even in those skirmishes that seem insignificant because the consequences of a defeat or victory will be dramatic.