A Parade of Black
A Gawd Oath is not sworn by one’s Honor. It is sworn by one’s patron Gawd. All persons have one. Even if you don’t, you unknowingly serve the general pantheon of your alignment. As such, it is the deities themselves who enforce these oaths. The Gawds do not take their names used in vain lightly. Still the Gawds do not seek to meddle with the affairs of mortals as we are so beneath them as well as to maintain the status quo amongst themselves so more oft than not their attention is short lived. The loss of 1 full level+ is about as much effort as they put in(be grateful as they could simply erase you). All Exp is lost from where you currently are all the way down to the first point of Exp of the previous level. So depending on how far in your progress to the next level, you may effectively loose two levels worth of Exp.
I.E. A level 2 character 1 point away from level 3 breaks his Gawd Oath. His patron Gawd is quite miffed about this and strikes the character with the level loss and he goes all the way down to his very first Exp point of Lv 1. Just a rat away from Lv 3 all the way back to Lv 1.
Don’t break Gawd Oaths.