Yoma 55 - He would count, "One, one-and-one, one-and-two," etc.
Having brought the incense to the Holy of Holies, the High Priest exits, takes the blood of the bull from the priest who was stirring it, and re-enters the Sanctuary and the Holy of Holies, and starts sprinkling the blood toward the Ark-cover, one time above and seven times below. The blood never really lands on the Arks itself, "up" and "down" refers to the direction of his fingers in a whipping motion.
To make sure that he maintains the correct count, he says out loud, "One, one-and-one, one-and-two… and so on.. one-and-seven." - since any mistake in the counting would invalidate the whole procedure.
The High Priest then takes the blood of the goat, puts down the blood of the bull, re-enters the Holy of Holies, and sprinkles the blood of the goat, counting again, "One, one-and-one, etc." Finally, he pours the bull's blood into the blood of the goat and then pours it all back to make the two types of blood thoroughly mixed.
Art: A Rocky Landscape With A Bull, Goat, Ram, And Sheepdog By Philipp Peter Roos
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