Halakha Yoel 2:13: Mishneh Torah, Fasts, Mishneh Torah, Foundations & Shulchan Arukh, Orach Chayim

And afterwards they should have a sage elder stand up among them [while] they sit. [If] there was not a sage elder there, they stand up a sage. [If] there was neither a sage nor an elder there, they stand up a man of stature. And he says words of submission in front of them: Our brothers, it is not sackcloth or fasting that cause [a divine punishment to end], but rather repentance and good deeds. As so did we find with Nineveh -d it is not stated about the people of Nineveh, "And God saw their sackcloth and their fasting"; but rather, "And God saw their deeds" (Jonah 3:10). And in the received tradition, it states (Joel 2:13), "Rend your hearts and not your garments." And he adds to these topics according to his ability, until they humble their hearts and repent with a complete repentance.

Concerning a prophet's prediction of calamities, such one would die, or such year would be visited by famine, or war, or matters similar to these, even though his words be not established, it is not considered contradictory to his prophecy. It shall not be said: "Behold, he spoke and it did not come to pass!" For, the Holy One, blessed is He! is long-suffering and abundant in goodness, and repenteth Him of the evil, and it is possible that they repented and were forgiven, as did the inhabitants of Nineveh,²Jonah, 3. 5-8 G. or that their fate was postponed, as was with Hezekiah.³Isa. 38; 11 Kings, 20.6 G. But if he assured that good would come to pass, saying that it would be thus and such, but the good he promised did not come to pass, it is certain that he is a false prophet, for every good thing God decides upon, even though it be contingent, He doth not repent. And, we find no instance when He repented from a good thing save only at the destruction of the First Temple, when he assured the righteous that they would not die together with the wicked and retracted it, as it appears in Tractat Shabbat⁴Shabbat, 55a. Because the wickedness was great, and the righteous did not sufficiently rebuke the evildoers. See Shabbat, 119b. G.. Herefrom we learn that a prophet is tested solely by his prophecy concerning good tidings, which is in harmony with what Jeremiah said in his reply to Hananiah son of Azzur, when Jeremiah was prophesying evil tidings and Hananiah good, saying unto him: "If my words will not be established, it would yet not be evidence that I am a false prophet; but if thy words be not established it will be proclaimed that thou art a false prophet". For it is said: "Nevertheless hear thou now this word that I speak in thine ears, and in the ears of all the people: The prophets that have been before me and before thee of old prophesied against many countries, and against many kingdoms, of war, and of evil, and of pestilence; the prophet that prophesieth of peace, when the word of the prophet shall come to pass, then shall the prophet be known, that the Lord hath truly sent him" (Jer. 28.7–9).

The order of prayer on these fasts, consisting of three sections:Every day from the seventh day of withholding rain, following the established order of these fasts, the people gather and go out with the ark to the city square. The entire community assembles, covering themselves with sackcloth and placing ash from burnt material (meaning ash from something that has been burned, distinct from regular dust, which is also called ash) on the ark and on the Torah scroll. This is done to intensify the weeping and to humble their hearts. One of the people takes the ash and places it on the head of the leader and the head of the court, in the place where they put on tefillin, so they may be ashamed and repent. Each person then takes and places it on his own head. Afterwards, they arrange a wise elder among them, and if there is no wise elder, they appoint a sage. If neither is present, they appoint someone of stature and say before them words of rebuke, meaning words that provoke and stir the heart towards repentance. They emphasize that neither sackcloth nor fasting alone cause repentance, but rather true repentance and good deeds. We find in the case of the people of Nineveh, it is not said, 'God saw their sackcloth and their fasting,' but rather, 'God saw their deeds.' In accordance with his ability, the person addressing them continues with these matters until he softens their hearts, and they fully repent. After concluding these words of rebuke, they stand in prayer and appoint a prayer leader suitable for these fasts. If the one who spoke the words of rebuke is fit to pray, he prays. If not, someone else is chosen to lead the prayer. Who is fit to lead the prayer on these fasts? A person who is accustomed to praying regularly, is familiar with reading from the Torah, Prophets, and Writings, is morally upright, has toiled in the field, has not had a child or relative who transgressed, has an empty house of transgressors, has not acquired a bad reputation in his youth, is humble, pleasant to people, and has a pleasant voice. If he is elderly, with all these qualities, he is honored. If not, as long as he possesses all these qualities, he should lead the prayer.