What is the story of returning Jiziah (tax) to non-Muslims when Muslims were unable to defend them?

Sometime, somewhere I heard a story something like this from context: > In one Muslim country when leaders were realized that they is going to be defeated by enemy, they started returning collected taxes from non-Muslims, justifying that, they can't provide them security anymore. After seeing that greatness, non-Muslim troops joined to Muslims troops and they defeated enemy together. I love this story so much, and I love to narrate this so often. To be more convincing, I'd love to know source of this story and maybe just more historical fact about this or is this hadith or anything ?