> But is there not a time when an evil ? a murder, an affair, whatever ? can present opportunity for growth?

It is never preferable, or "better" in the long run, to take a path through evil. God knows all, God knows what is best, what is holy, and so if God commands us one thing, and we do another, than this is, by nature, necessarily "worse" than if the evil had never been done.

That said, the Bible records one instance after another in which God, thanks to his grace, *uses* evil and turns it around for good. So to answer your question, yes, opportunities for good things can come about through evil. However, avoiding evil would still be "better."