The Lord instructed Moses,
“You shall also take the other ram, and Aaron and his sons shall put their hands on the head of the ram. Then you shall kill the ram, and take some of its blood and put it on the tip of the right ear of Aaron and on the tip of the right ear of his sons, on the thumb of their right hand and on the big toe of their right foot, and sprinkle the blood all around on the altar” (Exodus 29:19-20).
Moses was to take some of the blood of the ram and put it on:
The tip of the right ear
The thumb of the right hand
The big toe of the right food
By this Aaron and his sons, and the altar would be sanctified for the work for which God had selected them.
Blood dedicated everything in service to God (Hebrews 9:16-28 alludes to some of this), and this all prefigured the blood of Christ setting us apart to do His work.