Yoma, Chapter Five, Mishnah Three
In this mishnah the high priest takes the blood from the slaughtered bull and sprinkles the blood within the Holy of Holies.
1) He would take the blood from the one who was stirring it, and enter [again] into the place where he had entered, and stand [again] on the place on which he had stood, and sprinkle once upwards and seven times downwards, and he wouldnt intend to sprinkle either upwards nor downwards but rather like one who cracks a whip.
2) And thus would he count: one, one and one, one and two, one and three, one and four, one and five, one and six, one and seven.
3) Then he would go out and put it on the golden stand in the sanctuary.
Section one: The high priest now took the bulls blood from the person who was stirring it to keep it from congealing (see above 4:3). He then went back into the Holy of Holies and stood in the same place.
Leviticus 16:14 reads: He shall take some of the blood of the bull and sprinkle it with his finger over the cover (caporet) on the east side; and in front of the cover he shall sprinkle some of the blood with his finger seven times. The rabbis did not interpret this verse to mean that he sprinkled the blood directly onto the cover of the ark, the caporet. Rather over the cover meant one sprinkle was directed up and the seven that were in front of the cover were sprinkled downwards. The blood from all of the sprinkles was supposed to land on the ground. The way in which the high priest did this is described as being like one who cracks a whip. This means that the first sprinkling was done by the hand beginning below and cracking upwards and the seven other sprinklings were done with the hand beginning above and moving in a sharp direction below (pretend like you are cracking a whip and you will understand immediately what this means.)
Section two: The first one refers to the upwards sprinkling. When counting the lower seven sprinklings, he would count with each of them the one that he had done above. This was done so that he wouldnt make a mistake and count the upwards sprinkling with the downwards ones and thereby come up short by one sprinkling.
Section three: When done sprinkling the blood he would leave the Holy of Holies and take the bowl with the blood out and put it on a golden stand made especially for this purpose.