R’ Moshe of Kobrin zt’l wrote the following letter to his chassidim during the cholera plague:
Don’t allow what’s happening at this time to frighten you. Hashem is with us. Trust in Hashem and rely on Him. “When one trusts in Hashem, he is surrounded with kindness” (Tehillim 32:10)… As I told you before, when you have on Whom to rely, there is nothing to fear. Therefore, for Hashem’s sake, keep your spirits up. Each person should encourage his fellow man…
The counsel and the protection from this plague, r’l is that you shouldn’t be afraid…Be afraid from the One who brought the plague, and not from the plague itself. Keep your emunah and bitachon strong, because that is the best protection. Don’t stop saying the pasuk (Yeshayah 51:12), “Hashem is with us…” Hashem will protect you and your children.
Dear brothers…don’t fear anything but Hashem, alone. When you follow this counsel, the plague won’t harm you… Hashem’s sole desire is to protect you and to save you from all bad, and to bless you with all goodness. I will also pray for you wherever I go.
Dear brothers, be healthy, strong, and happy. Just don’t worry. May I merit seeing your salvation, in ruchniyos (spiritually) and gashmiyos (physically). So writes the one who is connected to you with a true love that endures forever.