“Sanctify a fast, call a solemn assembly, gather the elders and all the inhabitants of the land in the house of the Lord your God, and cry to the Lord in penitent pleadings.” Joel 1:14 Amplified
This fast in Joel was held during a time of great trouble. It appears he is urging all the people to gather together to fast, as opposed to an individual fast.
In our current culture of comfort this may be something outside the realm of most people. Our churches today though, need to periodically do this and specifically right now for our nation and the world. I am going to speak to my pastor about calling one and hope you will too.