After certain kinds of tragedies, there is often some discussion about why they happened -- in particular, why God didn't prevent them. "Where was God when ..." some tragedy struck?
It's an odd question in some ways. It's typically asked after man-made tragedies -- such as killing the innocent -- which God forbids. Often enough, we have a confused situation in which people blame God even though he forbids such an attack, but do not blame the people who carried out the attack. In some cases -- such as 9/11 -- we see people blame the victims or the victims' government as if the attack were a matter of justice on some level, and yet still blame God for allowing the attack which was deemed justified. That's not a consistent and sensible approach to justify the attacker but condemn God for allowing it. And it does nothing to honestly stand up against that kind of darkness, much less shed any light on the deeper issues of how (or if) God works for our good.
The "Where was God?" approach ignores God's prohibition against taking an innocent life, and still blames God when it happens. I'll set aside the atheists who take advantage of a tragedy to sow doubt, and mention: some may raise the question because they want to hope in God. But when it comes to God's approach to evil, they want more than opposition, they want prevention.
We may long for a world without tragedies. As long as there are people in the world who justify hatred, who encourage rage, who make excuses for killing the innocent, there will be tragedies. What if God were to take out these people before they act? But I am not convinced that pre-emptive strikes are justified. If we
blame God for anything that looks like judgment or punishment against
people who have clearly done wrong, how much more would we blame God for
acting against people who had not done wrong yet?
Those of us who are Christians start with the basic view that God is good. So it makes sense to look for God's goodness always, especially in the face of evil. The "Where was God?" argument assumes more than God's goodness, though; it assumes that God should solve problems in a certain way. I don't know that God's approach is about preventing tragedies so much as rendering them meaningless in the long run: he raises the dead. He makes the wounded whole again, and wipes away the tears. All the harm done will come undone.
I picture Jesus' crucifixion, where we have criminals facing execution, and some onlookers taking satisfaction that evil was being stomped out, one evildoer at a time. Where was Jesus? He was giving hope to the dying. And forgiving the executioners.