Who said "A man's word is his bond."?

This quote is attributed to Drogo.

A man's word is his bond. - Drogo

"A man's word is his bond."

Drogo

"I am the stallion who mounts the world"

"A Dothraki hears a word and takes it as a command"

"You are of my blood. That is enough"

"I will take what is mine with fire and blood"