I'm trying to find a book I read in the late '70s or early '80s.
In the book, the gods were active in the world, through their mortal champions. The gods spoke directly to their champions, and gave them guidance and tasks to perform.
The protagonist was a swordsman, a champion of the good-aligned warrior god.
The protagonist was of a race that was once known for their wise and thoughtful counsel, but through some kind of "deal-with-the-devil" with one of the evil gods, they now are subject to episodes of irrational berserker rage.
As a champion, the protagonist has special abilities granted to him, like being able to summon his sword magically from its scabbard directly into his empty hand with a single word.
At one point, he encounters a younger swordsman who is very full of himself, but the warrior god tells him not to kill the younger one, because he has plans for him. So, he uses the flat of his sword to break both of the kid's arms as a lesson in humility.
I remember having the impression that the book was one of a series, but I can't be certain of that.