Found just once in the New Testament (Heb. 12:20), and not used in all our manuscripts, the Greek noun “bolis” meant “dart,” “spear,” “arrow,” “projectile,” “javelin.” Any person or any animal that touched Mount Sinai, when God was communicating with His people, was to be put to death (“thrust through with a dart,” KJV).
More details about this event may be found in Ex. 19, but here we may make a simple observation. God abounds in love and mercy, and these wonderful qualities are in perfect harmony with the death penalty.
In this life, some sins merit physical death. In eternity, all sins merit eternal death (Rom. 6:23) if they are not forgiven.