Christ's resurrection teaches us that the apparently inevitable victory of evil is only apparently a victory, only apparently inevitable. But God shows that he can bring great good even out of something as horrific as deicide. More than that, God uses the very evils perpetrated on that weekend to bring about a tremendous good for those complicit in the crimes, persons accused of murdering the Son of God -- it means the joyful and unrestricted giving of the Holy Spirit to all who ask.
All this shows us God's power -- that he is wise enough and able to bring about tremendous good even from the most heinous evils. When we see the example of Christ's crucifixion and what became of it -- the salvation of the world, its reconciliation to God -- how can we have doubts about the eventual redemption of any of the evils we have known and experienced? How can we doubt that God will save and restore the entire world, if he can make use of deicide for the sake of the salvation of the deicidal? All of our suffering has been changed by Christ's suffering. All of our suffering is just a participation in Christ's crucifixion, after which we await a glorious restoration in resurrection.
All this shows us God's love and goodness -- that he would sooner die than to allow that his creation be undone and condemned forever. God is quick to forgive, and precisely for this reason he allows that he be nailed to a cross, spit on, his head beaten with reeds, his naked body burned by the unforgiving sun. John says, This is how God showed his love among us: he sent his one and only Son into the world that we might live through him. This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins (1 John 4.9-10). God loves the dead and through his Son gives them life; God loves sinners and through his Son atones for their evil. God's love for the entire world cannot be in doubt, when he makes himself one of us and undergoes the worst any of us can undergo, in solidarity in love with us to the very end and for our sake.
Importantly, too, Jesus' resurrection is eternal proof that this good God is sovereign over the world. The resurrection of the dead means the arrival once and for all of God's kingdom, the goal towards which all things are headed one way or another. There can be no doubts about God's sovereignty in the world when he can undo murder and turn it into an occasion for life. Moreover, we participate in that new kingdom through communion and union with Jesus Christ the risen one in the context of the church. Here I quote Moltmann:
Now the proclamation of the Easter witness that God has 'raised' this dead Jesus 'from the dead' amounts to nothing less than the claim that this future of the new world of the righteousness and presence of God has already dawned in this one person in the midst of our history of death. . . . Believers no longer live in this unredeemed world of death. In that one man the future of the new world of life has already gained power over this unredeemed world of death and has already condemned it to become a world that passes away. Therefore, in faith in the risen Jesus, men already live in the midst of the transitory world of death from the powers of the new world of life that have dawned in him. There is already true life in the midst of false life, though only in communion with the one who had been crucified by that false life. 'The future has already begun' (The Crucified God, pp. 170-1).
Now Jesus' resurrection is the goal towards which humanity is headed, as I've said. But that goal comes about in two ways, mirrored by the two descriptions of the quality of Christ's death on the cross in the synoptic gospels. In Matthew and Mark Jesus' death is a rather terrible and violent one, and he cries out in abandonment by God on the cross. In Luke and John he dies confidently, like a brave martyr, obedient and confident in God's will to the very end. Here we see the two ways we arrive at the goal of God's kingdom: those who are united to Christ, who know the truth, who have submitted themselves to him -- all such persons go confidently into God's kingdom; those who are not, who've defined themselves in opposition to Christ, must first go through the hellish experience of profound abandonment by God. But the end result is the same: in Christ all will be made alive (1 Cor 15.22).
Jesus' resurrection, finally, shows us that one can undergo the definitive eschatological punishment of God and be restored in the end. As for those who say that if hell is not eternal, there is nothing to fear about it -- they ought to "go to dark Gethsemane" and see the same Christ who knows he will be resurrected praying with hematidrosis.