Yoma, Chapter 6, Mishnah 2. We return now to the order of the service, the Yom Kippur service, after we finished with the sprinklings of the blood in the Heichal. Now the Mishnah turns back to the goat that is sent away.
The Kohen Gadol and the goat that is sent away:
The Kohen Gadol comes to the goat that is sent away - the one designated to be sent out - places both his hands upon it, and confesses. And this is the text of the confession:
"Ana Hashem, please Hashem, Your people the House of Israel have sinned. Please Hashem, grant atonement for the sins that they have sinned, for the House of Israel has sinned, as You wrote in the Torah of Moshe Your servant, saying: 'For on this day He shall atone for you, to purify you from all your sins; before Hashem you shall be purified.'"
The response of the kohanim and the people:
The kohanim and the people standing in the Azarah, upon hearing the explicit Name come from the mouth of the Kohen Gadol, would do the following:
They would kneel.
They would bow and fall on their faces.
And they would say - and here the Mishnah expands and brings the full text of what they said.
They would do this every single time they heard the explicit Name.
In summary: These are the very words we use when we recite the order of the service. When we repeat the order of the service in the Mussaf prayer of Yom Kippur, we use this same language ourselves, at the moment when we bow during the prayer.