Alma 4

After a significant war with the Amlicites and the Lamanites, Mormon records -

"...the people were afflicted, yea, greatly afflicted for the loss of their brethren, and also for the loss of their flocks and herds, and also for the loss of their fields of grain, which were trodden under foot and destroyed by the Lamanites.
3 And so great were their afflictions that every soul had cause to mourn; and they believed that it was the judgments of God sent upon them because of their wickedness and their abominations; therefore they were awakened to a remembrance of their duty.
4 And they began to establish the church more fully..."  (Alma 4:2–4)

This may be why the Lord has allowed the invisible war of Covid-19 in our day.