Saint Thomas Aquinas said that God and the problem of evil is the most challenging problem to the existence of God. For Thomas, the solution is that God only permits evil, when he can bring some greater good out of it. God never causes evil, because God is all-good.
But it is true that we cannot always see the good that comes out of evil. Houselander echoes the challenge this brings. But she also speaks the truth concerning God, and how he is with us in the face of evil.
For we could think it best if God prevented all evil. But to do so would also prevent us from being made in God’s image and likeness, since we would not be free. So it is that God shows us his face in a small, humble way. “The beginning of recognition will consist in knowing what sort of thing to expect.”