Numbers 21:8-9
8 And the LORD said unto Moses, Make thee a fiery serpent, and set it upon a pole: and it shall come to pass, that every one that is bitten, when he looketh upon it, shall live.
9 And Moses made a serpent of brass, and put it upon a pole, and it came to pass, that if a serpent had bitten any man, when he beheld the serpent of brass, he lived.
I. This history would sound a strange one, and would suggest some mystery underlying it, even if it stood alone, with no afterword of Scripture claiming a special significance for it. But it is stranger and more mysterious still when we come to our Lord's appropriation of it to Himself (John 3:14). It is strange and most perplexing to find the whole symbolism of Scripture on this one occasion reversed, and Christ, not Satan, likened to the serpent here. How shall we account for this? What can be the points of comparison? Many answers have been given to this question, but there is only one which really meets the difficulties of the case. As a serpent hurt and a serpent healed, so, in like manner, as by man came death, by man should come also the resurrection from the dead; "as by one man's disobedience many were made sinners, so by the obedience of one should many be made righteous."
II. The brazen serpent, so like in colour, in form, in outward show, to those that hurt the people, was yet unlike in one point, and that the most essential point of all: in this, namely, that it was not poisonous, as they were. Exactly so the resemblance of Christ to His fellow-men, most real in many things, was in one point only apparent. He only seemedto have that poison which they really had. He was harmless, holy, undefiled, separate from sinners.
III. We may imagine that in some of the Israelites perverse thoughts may have been at work, inducing them to make in the very presence of life a covenant with death. So we, giving way to similar temptations, but in a far guiltier spirit of unbelief, may be refusing to look at Him who, though crucified in weakness, is yet "the power of God unto salvation in every one that believeth."
R. C. Trench, Sermons Preached in Ireland,p. 228.
References: Numbers 21:9. T. Champness, Little Foxes,p. 132; W. Walters, Christian World Pulpit,vol. xx., p. 237; Spurgeon, Sermons,vol. xxv., No. 1500; Clergyman's Magazine,vol. viii., p. 214.Numbers 21:16. Spurgeon, Sermons,vol. xiii., No. 776. Numbers 21:17. G. Litting, Thirty Children's Sermons,p. 197; Spurgeon, Evening by Evening,p. 169. Numbers 21:22. Clergyman's Magazine,vol. x., p. 156. Numbers 21 W. M. Taylor, Moses the Lawgiver,p. 374.Numbers 22:1. Clergyman's Magazine,vol. iv., p. 207. Numbers 22:2. Expositor,2nd series, vol. v., p. 11.Numbers 22:10. E. W. Shalders, Christian World Pulpit,vol. xvi., p. 296. Numbers 22:12. Sermons for the Christian Seasons,1st series, vol. ii., p. 477. Numbers 22:12. Clergyman's Magazine,vol. xvi., p. 204.Numbers 22:15. Homiletic Quarterly,vol. iii., p. 97. Numbers 22 Expositor,2nd series, vol. i., p. 445.