There is no solution or explanation for evil. Evil is fundamentally irrational; it simply cannot be grasped by means of our intellectual categories. Evil is the very denial of rationality, because it is a rebellion against the Logos, the very principle of the good, the true, and the beautiful who created and sustains the universe.
And who has redeemed the universe. The Christian hope in the face of evil is not to explain it or cure it. Our hope is absurd in its own way, turning absurdity on its head. We proclaim that evil has already been dealt the decisive blow. And that blow was delivered, paradoxically enough, at a moment when evil seems to have won—on the cross on which Jesus Christ died.
Christians "make sense" of tragedies by acknowledging that they are in fact senseless, and that their absurdity is little different than the absurdity of the Cross. And that's precisely why, when we talk about the gospel, we begin with the absurd. As Paul notes, our preaching is
foolish to the Jews, who ask for signs from heaven. And it is foolish to the Greeks, who seek human wisdom. So when we preach that Christ was crucified, the Jews are offended and the Gentiles say it’s all nonsense. (1 Cor. 1:22-23 , NLT)
And the content of the preaching is this: absurdity has been defeated by absurdity, death has been defeated by death. The Resurrection, especially in the preaching in Acts, is mostly about the vindication of Jesus ("Jesus, whom you crucified, has been exalted by God, so ha!"—see Peter's speech in Acts 2). The apparent failure of the Cross was, in fact, a victory—a victory over the irrational principalities that currently wreak havoc in the world, represented by those little key chains we carry around. (So maybe it's a sign of good theology to carry something silly on our key chains—it shows we're not taking evil as seriously as it takes itself!)
The commenter quoted above also waxed theological, something a lot of people, believers and not, are doing:
Why weren't those who were Mercilessly Slaughtered Prayers to Live heard I wonder. Evidently God was too busy planning with Tebow for Touchdowns this Fall to check his Voicemail. It just makes NO sense to me to Pray to a God that can't stop such things from happening in The 1st Place.What kind of God who is truly all powerful,Just or Loving just sits back&let's innocent People die&then has them believing it's THEIR Fault? Certainly not one I'd Pray to,or even bother with. That's like saying they deserved their Fate because someone else they never met did something Bad. It's a slap in the face when they say such things.
It does make even the faithful wonder "what kind of God" we have put our faith in. Apparently he is a God who does not intervene to prevent such horrors, for reasons we, as much as this commenter, find unfathomable. It is indeed a slap in the face to people when we use a thin veneer of pop theology to "explain" the tragedy. Better just to confess, as did David, time and again in the Psalms,
Lord, . . . you hid your face;
I was dismayed. (Ps. 30:7)
This Psalm, coincidently enough, was the reading for the day after the shooting. But actually, that's not such a coincidence, because lots of Bible passages note this reality, the feeling that God is hiding himself. Many a saint, like their Lord, has felt utterly forsaken. The Bible is pretty frank about this reality.