On Public Repentence

"Blow ye the trumpet in Zion,
and sound an alarm in my holy
mountain: let all the inhabitants
of the land tremble: for the day
of the LORD cometh, for it is
nigh at hand," (Joel 2:1).

"...[T]his passage shows that when any judgment of God is impending, and tokens of it appear, this remedy ought to be used, namely, that all must publicly assemble and confess themselves worthy of punishments and at the same time flee to the mercy of God. This, we know, was, as I have already said, formerly enjoined on the people; and this practice has not been abolished by the gospel. And it hence appears how much we have departed from the right and lawful order of things; for at this day it would be new and unusual to proclaim a fast. How so? Because the greater part are become hardened; and as they know not commonly what repentance is, so they understand
not what the profession of repentance means; for they understand not what sin is, what the wrath of God is, what grace is. It is then no wonder that they are so secure, and that when praying for pardon is mentioned, it is a thing wholly unknown at this day. But though people in general are thus stupid, it is yet our duty to learn from the Prophets what has always been the actual mode of proceeding among the people of God, and to labor as much as we can, that this may be known, so that when there shall come an occasion for a public repentance, even the most ignorant may understand that this practice has ever prevailed in the Church of God, and that it did not prevail through inconsiderate zeal of men, but through the will of God himself."

~~John Calvin, Commentary on the Prophet Joel, Lecture Forty-First (Joel 2:1-11).