Our story picks up steam here. In yesterday's reading we saw Satan basically challenge God to a bet. Satan alleged that Job worshiped God only because God had been so good to Job. Satan says if God "stretches out his hand" meaning taking Job's prosperity away, Job will curse God. God then allows Satan to attack Job's possessions, but not to hurt Job himself. It's interesting that in this case, children count as possessions. The whole scenario is quite troubling, but it does set up a good story.
For the record, I don't think God actually acts like this.