John 3:13-16

13 And no man hath ascended up to heaven, but He that came down from heaven, even the Son of man which is in heaven.

14 And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up:

15 That whosoever believeth in Him should not perish, but have eternal life.

16 For God so loved the world, that He gave His only begotten Son, that whosoever believeth in Him should not perish, but have everlasting life.

ascended — as opposed to Enoch (translated — Hebrews 11:5), to Elijah (went up — 2 Kings 2:11), raptured saints (caught up — 1 Thessalonians 4:17).

up to heaven — the third heaven, when God dwells

who is in heaven — His omnipresence. While on earth as a man, He was also in heaven as God. This is tied to verse 12. Jesus could speak with authority about heavenly things because He was from heaven.

serpent — sin. A reminder of the curse. Christ was cursed for us. Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth on a tree (Galatians 3:13). The serpent was made of brass (see Numbers 21:4-9 at the end of this post), signifying Divine judgment (Deuteronomy 28:23, Revelation 1:15).

lifted up — Jesus was informing Nicodemus that before He comes in glory as king, He must suffer. He is referring to the crucifixion. And I, if I be lifted up from the earth, will draw all men unto Me. This He said, signifying what death He should die (John 12:32-33).

must be lifted up —  The righteousness of God demands it.

The brazen serpent lifted up on a pole is the type of Christ in His sacrificial work on the cross. That serpent was the very image of what was destroying the Israelites, but the brazen serpent had no poisonous fangs; there was no poison in it. Though it bore the likeness of the serpent, the emblem of sin, it was harmless. Thus the Son of God appeared in the form of a man, in the likeness of sinful flesh (Romans 8:3), but He was without sin; He knew no sin. And when He was lifted up on the cross, on that cross He who knew no sin was made sin for us, and by the offering of Himself for sin, He put away sin. Hanging on that cross He bore the curse, being made a curse for us, for it is written, “Cursed is everyone that hangeth on a tree” (Galatians 3:13). Looking up to the brazen serpent, the Israelites saw the very thing which had put death and ruin upon them, triumphed over, completely conquered. And so as we look to Christ crucified, made a curse, bearing sin, we see sin judged, condemned, triumphed over, robbed of its power and stripped of its strength. — Gaebelein, page 69.

world/whosoever — everyone, not just the elect

Verse 15 — believe in the Son of man. Verse 16 — believe in the Son of God. To be saved, we must believe in His two-fold nature.

only begotten — eternal Sonship

so loved — magnitude

gave — giving love, unselfish

God’s love resulted in Christ’s sacrifice, not the other way around. In this was manifested the love of God toward us, because that God sent His only begotten Son into the world, that we might live through Him. Herein is love, not that we loved God, but that He loved us, and sent His Son to be the propitiation for our sins (1 John 4:9-10).

Man became a lost sinner by a look, for the first thing recorded of Eve in connection with the fall of our first parents is that “The woman saw that the tree was good for food” (Genesis 3:6). In like manner, the lost sinner is saved by a look. The Christian life begins by looking: “Look unto me, and be ye saved, all the ends of the earth: for I am God, and there is none else” (Isaiah 45:22). The Christian life continues by looking: “let us run with patience the race which is set before us, looking unto Jesus the author and finisher of faith” (Hebrews 12:2). And at the end of the Christian life we are still to be looking for Christ: “For our conversation (citizenship) is in heaven; from whence also we look for the Savior, the Lord Jesus Christ” (Philippians 3:20). From first to last, the one thing required is looking at God’s Son. — Pink, page 134-135.

Numbers 21:4-9 — And they [Israelites] journeyed from mount Hor by the way of the Red sea, to compass the land of Edom: and the soul of the people was much discouraged because of the way. And the people spake against God, and against Moses, Wherefore have ye brought us up out of Egypt to die in the wilderness? for there is no bread, neither is there any water; and our soul loatheth this light bread. And the Lord sent fiery serpents among the people, and they bit the people; and much people of Israel died. Therefore the people came to Moses, and said, We have sinned, for we have spoken against the Lord, and against thee; pray unto the Lord, that He take away the serpents from us. And Moses prayed for the people. 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. 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.