Nicene and Post-Nicene Fathers, Vol. V:
A Treatise on the Merits and Forgiveness...: Chapter 61

Chapter 61 [XXXII.]—The Serpent Lifted Up in the Wilderness Prefigured Christ Suspended on the Cross; Even Infants Themselves Poisoned by the Serpent’s Bite.

And since this great and wonderful dignity can only be attained by the remission of sins, He goes on to say, “And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up; that whosoever believeth in Him should not perish, but have eternal life.” 428 We know what at that time happened in the wilderness. Many were dying of the bite of serpents: the people then confessed their sins, and, through Moses, besought the Lord to take away from them this poison; accordingly, Moses, at the Lord’s command, lifted up a brazen serpent in the wilderness, and admonished the people that every one who had been serpent-bitten should look upon the uplifted figure. When they did so they were immediately healed. 429 What means the uplifted serpent but the death of Christ, by that mode of expressing a sign, whereby the thing which is effected is signified by that which effects it? Now death came by the serpent, which persuaded man to commit the sin, by which he deserved to die. The Lord, however, transferred to His own flesh not sin, as the poison of the serpent, but He did transfer to it death, that the penalty without the fault might transpire in the likeness of sinful flesh, whence, in the sinful flesh, both the fault might be removed and the penalty. As, therefore, it then came to pass that whoever looked at the raised serpent was both healed of the poison and freed from death, so also now, whosoever is conformed to the likeness of the death of Christ by faith in Him and His baptism, is freed both from sin by justification, and from death by resurrection. For this p. 40 is what He says: “That whosoever believeth in Him should not perish, but have eternal life.” 430 What necessity then could there be for an infant’s being conformed to the death of Christ by baptism, if he were not altogether poisoned by the bite of the serpent?

Footnotes

John 3:14, 15.

Numb. xxi. 6-9.

John iii. 15.