Jesus says that in the days leading up to His second coming, people will be totally unaware of what is about to happen to them. They will be "eating and drinking, marrying and giving in marriage," just as people were in the days leading up to the flood in the time of Noah. In the same way that "they were unaware until the flood came and swept them all away," so also many will be equally unaware when Christ returns and the day of the flood of God's judgment comes upon the earth and sweeps them away (Matt. 24:36–39). It is a sobering thought, to be sure, but one that ought to give us a great appreciation for the glorious truths of the gospel clearly articulated in passages such as John 3:16.
Among the things of which John 3:16 assures us is that God will be merciful to all who put their hope and trust in Jesus Christ. Believers need not fear the coming flood of God's judgment because we know that God gave His Son for the express purpose that all who believe in Him "should not perish." That is one of the glorious truths held out to us in this well-known verse, as we will see.
Although it is true that the word perish is used frequently in the Gospels to refer to physical death or destruction (approximately thirty-six out of the sixty-six occurrences), it means far more than that here in this passage. We know that to be the case because the word "perish" is placed in antithesis to "eternal life" in verse 16, "saved" in verse 17, and "not condemned" in verse 18. The destruction from which believers are spared in John 3:16 is, therefore, not physical death or even some kind of annihilation but the eternal destruction that results from being "condemned" because of sin and rebellion. All who reject Christ and persist in their unbelief will receive not eternal life but eternal destruction. The "wrath of God" will "remain" on them forever (v. 36).
This understanding of the word perish is in keeping with Jesus' teaching about hell. In Matthew 25:31–46, for example, Jesus sets the "eternal life" that is reserved for "the righteous" over against the "eternal fire" (v. 41) and the "eternal punishment" (v. 46) that is reserved for everyone else (referred to as both "goats" who do not follow the shepherd and as "cursed"). Those who do not receive eternal life do not simply die or cease to exist. They experience an eternity of "destruction" or "punishment" that manifests itself in "unquenchable fire" (Matt. 18:8; Mark 9:43, 48; Luke 3:17) or in the "fiery furnace" in which "there will be weeping and gnashing of teeth" (Matt. 13:42, 50). This is what it means to perish. It is an eternity of getting what our sins and our rejection of Jesus Christ deserve.
And this is precisely why John 3:16 is so encouraging for the Christian. It holds out to us the promise that "whoever believes" in Jesus Christ will not perish. Although our sins and our rebellion clearly deserve an eternity of destruction, that is not what we will receive from God. He will be merciful. He will spare us from destruction. He will not give us what we deserve. Jesus has ensured that. Thanks be to God for His inexpressible gift (2 Cor. 9:15).
But John 3:16 also stands as a warning that there are only two types of people in the world: those who are perishing and those who believe in the Son and are thus spared from perishing; those who "remain" under God’s wrath for eternity and those who believe and receive eternal life instead (John 3:36). Each person's response to Jesus determines which of the two categories he or she is in. Those who respond to Him in faith and obedience (which is the fruit and, thus, the proof of genuine faith) will not perish but will have eternal life. Those who do not respond in faith and obedience will not be shown mercy. The wrath of God will remain on them for eternity.
The good news of John 3:16 is that, though we were all at one time numbered among the perishing, now, through faith in Christ alone, that is no longer the case. We have been shown mercy. And for that reason, we will not perish.