John Gill's Exposition of the Whole Bible
Numbers 19:4
And Eleazar the priest shall take of her blood with his finger,.... He took the blood in his left hand, and sprinkled it with the finger of his right hand, as Maimonides says a; and so the Targum of Jonathan, which says, he did not receive it into a vessel, but into the palm of his hand, and from thence sprinkled it with his finger b: which Ainsworth thinks signified the Spirit of Christ, our high priest, called "the finger of God", Luke 11:20; who takes the blood of Christ, and sprinkles it on the hearts of his people, whereby they are freed from an evil conscience:
and sprinkle of her blood directly before the tabernacle of the congregation seven times; or "towards the tabernacle", so Noldius c; as sprinkling of the blood was the principal action in sacrifices, this was to be done directly before the tabernacle, from whence its purifying virtue was expected, though it was not shed in it, that it might have all the appearance of a sacrifice it could have; and being done seven times, denotes the perfection of it: the priest, when he sprinkled, stood on the east side, with his face to the west. When the temple was built at Jerusalem, this affair was transacted on the mount of Olives, which was east of Jerusalem. Jarchi says, the priest stood in the east of Jerusalem, and placed himself so that he might see the door of the temple at the time of sprinkling the blood. Now it appears, as Maimonides says d, that the floor of the temple was higher than the floor of the eastern gate of the mountain of the house twenty two cubits, and the height of the gate of the mountain of the house was twenty cubits; wherefore one that stood over against the eastern gate could not see the door of the temple, therefore they made the wall, which was over the top of this gate (the battlement of it), low, so that he (the priest), that stood on the mount of Olives, might see the door of the temple, at the time he sprinkled the blood of the cow over against the temple; otherwise he could only have seen the eighth step of the porch of the temple, as the same writer observes e, with which agrees the Misnah f, that all the walls there (about the mountain of the house) were high, except the eastern wall, that so the priest that burnt the cow might stand on the top of the mount of Olives, and look and behold the door of the temple, when he sprinkled the blood.
a Hilchot Parah Adumah, c. 3. sect. 2. b Vid. Misn. Parah, c. 3. sect. 7. c P. 81. No. 379. d Hilchot Beth Habechirah, c. 6. sect. 2. e In Misn, Middot, c. 2. sect. 4. f Misn. ib.