ספֿרי מצוות אויף במדבר 10:10

It is a positive commandment from the Torah to cry out and to sound trumpets for all troubles that come upon the community; as it is stated (Numbers 10:9), "upon an enemy who attacks you and you sound trumpets." That is to say, [with] every matter that troubles you — such as famine, a plague, locusts and that which is similar to them — cry out about them, and sound the trumpets.

And this thing is from the ways of repentance. For when a trouble comes and they yell out about it and sound [trumpets], everyone will know that it was because of their evil deeds that this bad was done to them. As it is stated (Jeremiah 5:25), "It is your iniquities that have diverted, etc." And this is what will cause them to remove the trouble from upon them.

But if they do not cry out and sound [trumpets], but rather say, "What has happened to us is the way of the world, and this trouble is merely happenstance" — it is surely the way of cruelty, and it causes them to stick to their bad deeds. And the trouble will add other troubles. About this is it written in the Torah (Leviticus 26: 27-28), "but walk arbitrarily with Me. Then I will (also) walk arbitrarily with you in fury." That is to say, "When I will bring upon you troubles — if you will say that it is arbitrary, I will increase the fury of this arbitrariness."