Reference: Thumb
Hastings
The thumb is associated with the great toe, and occurs in two different connexions. 1. We are told that Adonibezek's thumbs and great toes were cut off (Jg 1:8), and that he himself had practised this mutilation on seventy kings (Jg 1:7). The object seems to have been to render the vanquished monarchs unfit for war and thus for reigning in a warlike age. 2. In the ritual of the consecration of Aaron and his sons (Ex 29:20; Le 8:23-24) blood was sprinkled on 'the tip of the right ear, upon the thumb of the right hand and the great toe of the right foot.' The cleansed leper was similarly sprinkled with blood and oil (Le 14:14,17,25,28). The action seems to have symbolized the consecration (or purification) of the whole man, the extremities only being touched, just as only the horns of the altar were sprinkled with the blood.
W. F. Boyd.