Chapter 2 of Maseches Ta'anis, Mishnah 1. The mishnayos before us deal with the order of the prayers and the order of the blowing of the shofar and the trumpets - exactly how things were conducted during the last seven fast days that were decreed upon the community.
"Seder ta'aniyos keitzad":
The Mishnah opens by asking what the order of these fast days was, the last seven of them, and answers: "Motzi'in es ha'teivah lirchovah shel ir" - they would take the Aron Kodesh with the Torah scrolls inside it and bring it out to the main street, to the central thoroughfare of the city. In doing so they were making a statement: until now we cried out to Hashem inside the shul, in private, and we were not answered; from now on we will shame ourselves in public. Taking the Aron out expresses that we had a modest vessel, the Aron Kodesh, and because of our sins it was disgraced and we were forced to bring it outside together with us.
Once the teivah had been brought out, came the order of placing the ashes:
"V'nosen efer mikleh al gabei ha'teivah" - they place ashes on top of the Aron Kodesh, to symbolize that the Holy One, blessed is He, is, as it were, in distress together with us, as is symbolized by the Aron Kodesh.
"U'v'rosh ha'nasi v'rosh ha'Levi'im" - ashes were placed also on the head of the nasi, the head of the Sanhedrin, and on the head of the Levi'im, which is a sort of deputy position. And these men would ask others to place the ashes on their heads, so that the humiliation would be even greater.
"V'chol echad v'echad nosen b'rosho" - the rest of the community, each and every one would place the ashes on his own head, and did not need someone else to do it for him.
Words of rebuke:
The Mishnah continues: "Ha'zaken she'bahem omer lifneihem divrei kivushin" - the oldest and most senior member of the community would speak before them words that subdue the heart, words of mussar.
And this is what he would say to them: My brothers, it does not say about the people of Nineveh, when they did teshuvah following the words of Yonah, that the Holy One, blessed is He, saw their sackcloth and their fasting, but rather that He saw their deeds - for they turned away from their evil path. That is the teshuvah that the Holy One, blessed is He, seeks. He does not focus so much on the external things a person does, but on the inner ones.
And as the prophet Yoel says: "Rend your hearts and not your garments" - the tearing of garments is nothing more than an external symbol, while what is incumbent upon a person is to carry out the inner symbol: to tear his heart, meaning that he truly changes his heart and makes it different from what it was before.
In summary: In this section we learned the order of the last seven fast days: bringing the teivah out to the main street of the city as an expression of public shame, placing ashes on top of the teivah, on the head of the nasi and the head of the Levi'im and on the head of each and every person, and the words of rebuke of the elder of the community - that the essence of teshuvah is not in the external sackcloth and fasting but in turning away from the evil path and in the tearing of the heart.
Next we will deal with the order of the prayers and the order of the blowing of the shofar and the trumpets on the fast days.