The Two Towers, Chapter 5
Tolkien here draws together two ideas which Gimili naively thinks to be exclusive of one-another. This is similar to Lewis’ comment that the lion is good and dangerous. The lion is certainly not safe.
The source of this idea is God himself. God is good, perfectly good. God is love. Who has ever been more kind than Christ? And yet God is very dangerous; more dangerous than anything we could imagine: more dangerous than anything you will ever meet:
And do not fear those who kill the body but cannot kill the soul. Rather fear him who can destroy both soul and body in hell.
It is a simplistic concept to think that danger and good are separate.
This helps a bit understand the tension in Christianity that we are to love God, trust God, put our hope in God – fear God.