Numbers 21:8

Make thee a fiery serpent - i. e. a serpent resembling in appearance the reptiles which attacked the people. The resemblance was of the essence of the symbolism (compare 1 Samuel 6:5). As the brass serpent represented the instrument of their chastisement, so the looking unto it at God’s word denoted acknowledgment of their sin, longing for deliverance from its penalty, and faith in the means appointed by God for healing. In the serpent of brass, harmless itself, but made in the image of the creature that is accursed above others Genesis 3:14, the Christian fathers rightly see a figure of Him John 3:14 who though “holy, harmless, undefiled, separate from sinners” Hebrews 7:26, was yet “made sin” 2 Corinthians 5:21, and “made a curse for us” Galatians 3:13. And the eye of faith fixed on Him beholds the manifestation at once of the deserts of sin, of its punishment imminent and deprecated, and of the method of its remission devised by God Himself.