John 6:40
Perhaps some one will say, “When will be the consummation? When will be the Resurrection? See how long a time has gone by, and nothing of the kind has come to pass?” Yet it shall be, be sure. For those before the flood spoke after this manner, and mocked at Noah, but the flood came and swept away all those unbelievers, but preserved him who believed. And the men of Lot's time expected not that stroke from God, until those lightnings and thunderbolts came down and destroyed them all utterly.
Neither in the case of these men, nor of those who lived in the time of Noah, was there any preamble to what was about to happen, but when they were all living daintily, and drinking, and mad with wine, then came these intolerable calamities upon them. So also shall the Resurrection be; not with any preamble, but while we are in the midst of good times. Wherefore Paul says, “For when they shall say, Peace and safety; then sudden destruction comes upon them, as travail upon a woman with child; and they shall not escape.” God has so ordered this, that we may be always struggling, and be not confident even in time of safety.
What do you say? Do you not expect that there will be a Resurrection and a Judgment? The devils confess these, and are you shameless? “Have You come,” they say, “to torment us before the time?”; now they who say that there will be “torment;” are aware of the Judgment, and the reckoning, and the vengeance. Let us not then besides daring evil deeds, anger God by disbelieving the word of the Resurrection. For as in other things Christ has been our beginning, so also has He in this; wherefore He is called “the first-born from the dead.” Now if there were no Resurrection, how could He be “the first-born,” when no one of “the dead” was to follow Him?
If there were no Resurrection, how would the justice of God be preserved, when so many evil men prosper, and so many good men are afflicted and die in their affliction? Where shall each of these obtain his deserts, if so be that there is no Resurrection? No one of those who have lived aright disbelieves the Resurrection, but every day they pray and repeat that holy sentence, “Your Kingdom come.” Who then are they that disbelieve the Resurrection? They who have unholy ways and an unclean life: as the Prophet says, “His ways are always polluted.
Your judgments are far above out of his sight.” For a man cannot possibly live a pure life without believing in the Resurrection; since they who are conscious of no iniquity both speak of, and wish for, and believe in it, that they may receive their recompense. Let us not then anger Him, but hear Him when He says, “Fear Him which is able to destroy both body and soul in hell”; that by that fear we may become better, and being delivered from that perdition, may be deemed worthy of the Kingdom of Heaven. Which may we all attain to, through the grace and loving-kindness of our Lord Jesus Christ, by whom and with whom to the Father and the Holy Ghost be glory, now and ever and to the endless ages of eternity. Amen.
Source: Homilies on the Gospel of John (New Advent)