If you could go back in time, what would you change? Are there horrible things you would prevent?
If you changed the past, would you change the present in ways that make you sad? As brutal as the events of the past have sometimes been, have they born good fruit in the present?
God can see all through time as though it is the present for him. Our future is just as real for him as our present. If he intervenes in our world today, in ways we may sometimes be desperate for, he might rob our future of something important to us or our children.
We see through a glass darkly. He understands our pain in the present, but he can weigh that against our glorious future. Trust him, even in trials. Especially in trials.