Do Not Defile the Soul With Despair
Emunah & bitachon
The Torah commands a Kohen not to defile himself for a dead person among his kin (Vayikra 21:1). The Izhbitzer reads this verse as a warning against the defilement of the soul. The soul becomes defiled when it is infected by the bitterness and rage that follow senseless suffering and tragedy. Those who, like the Kohanim, are meant to serve Hashem are commanded to find within themselves the strength to resist the defilement of despair and darkness. Despair is the ultimate denial of Hashem, and to surrender to darkness is the gravest betrayal of faith.
Source: Mei Hashiloach, on Vayikra 21:1