Quick question. Are you talking about control/battle design? Or plot?
These are two different things.
You make a pledge to "never retreat from danger" not only is running now disabled, but controls can be tweaked so that you cannot go back a screen (the otherwise teleport event reminds you of your pledge), but walking is such that if you are facing left, you cannot go right, if you are facing up, you cannot go down. You have to turn a few times to go in the opposite direction.
Likewise, a magical oath of poverty prevents you from getting money/spending money in town. You have to harvest items to heal.
A plot-based oath is rather easy to do, but adds little to the game, as characters don't follow it when outside cutscenes.