Numbers 21:8

And the physiological discussion concerning the Son of God in the Timæus of Plato, where he says, “He placed him crosswise in the universe,” he borrowed in like manner from Moses; for in the writings of Moses it is related how at that time, when the Israelites went out of Egypt and were in the wilderness, they fell in with poisonous beasts, both vipers and asps, and every kind of serpent, which slew the people; and that Moses, by the inspiration and influence of God, took brass, and made it into the figure of a cross, and set it in the holy tabernacle, and said to the people, “If ye look to this figure, and believe, ye shall be saved thereby.” And when this was done, it is recorded that the serpents died, and it is handed down that the people thus escaped death. …

8. But as many as feared God, and were anxious about His law, these ran to Christ, and were all saved. For He said to His disciples: “Go ye to the sheep of the house of Israel, which have perished.” And many more Samaritans, it is said, when the Lord had tarried among them, two days, “believed because of His words, and said to the woman, Now we believe, not because of thy saying, for we ourselves have heard [Him], and know that this man is truly the Saviour of the world.” And Paul likewise declares, “And so all Israel shall be saved;” but he has also said, that the law was our pedagogue [to bring us] to Christ Jesus. Let them not therefore ascribe to the law the unbelief of certain [among them]. …

Likewise, when forbidding the similitude to be made of all things which are in heaven, and in earth, and in the waters, He declared also the reasons, as being prohibitory of all material exhibition of a latent idolatry. For He adds: “Thou shalt not bow down to them, nor serve them.” The form, however, of the brazen serpent which the Lord afterwards commanded Moses to make, afforded no pretext for idolatry, but was meant for the cure of those who were plagued with the fiery serpents. I say nothing of what was figured by this cure. …

To these are added those heretics likewise who are called Ophites : for they magnify the serpent to such a degree, that they prefer him even to Christ Himself; for it was he, they say, who gave us the origin of the knowledge of good and of evil. His power and majesty (they say) Moses perceiving, set up the brazen serpent; and whoever gazed upon him obtained health. Christ Himself (they say further) in His gospel imitates Moses’ serpent’s sacred power, in saying: “And as Moses upreared the serpent in the desert, so it behoveth the Son of man to be upreared.” Him they introduce to bless their eucharistic (elements). Now the whole parade and doctrine of this error flowed from the following source. They say that from the supreme primary Æon whom men speak of there emanated several other inferior Æons. To all these, however, there opposed himself an Æon who name is Ialdabaoth . …

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.” 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. …

11. He endured death, then; but death He hanged on the cross, and mortal men are delivered from death. The Lord calls to mind a great matter, which was done in a figure with them of old: “And as Moses,” saith He, “lifted up the serpent in the wilderness, so must the Son of man be lifted up; that every one who believeth on Him may not perish, but have everlasting life.” A great mystery is here, as they who read know. Again, let them hear, as well they who have not read as they who have forgotten what perhaps they had heard or read. The people Israel were fallen helplessly in the wilderness by the bite of serpents; they suffered a great calamity by many deaths: for it was the stroke of God correcting and scourging them that He might instruct them. …

4. “Remember Thou Thy congregation, which Thou hast possessed from the beginning” ( ver. 2 ). Can this by any means be the voice of the Gentiles? Hath He possessed the Gentiles from the beginning? Nay, but He hath possessed the seed of Abraham, the people of Israel even according to the flesh, born of the Patriarchs our fathers: of whom we have become the sons, not by coming out of their flesh, but by imitating their faith. But those, possessed by God from the beginning, what befell them? “Remember Thy congregation which Thou hast possessed from the beginning. Thou hast redeemed the rod of Thine inheritance.” That same congregation of Thine, being the rod of Thine inheritance, Thou hast redeemed. …

8. For a sign that shall be spoken against . By a sign, we properly understand in Scripture a cross. Moses, it is said, set the serpent “upon a pole.” That is upon a cross. Or else a sign is indicative of something strange and obscure seen by the simple but understood by the intelligent. There is no cessation of controversy about the Incarnation of the Lord; some asserting that he assumed a body, and others that his sojourn was bodiless; some that he had a passible body, and others that he fulfilled the bodily œconomy by a kind of appearance. Some say that his body was earthly, some that it was heavenly; some that He pre-existed before the ages; some that He took His beginning from Mary. It is on this account that He is a sign that shall be spoken against.