# the ones between whom the controversy exists

"the ones who disagree with one another"

# must stand before Yahweh, before the priests and the judges

This means the two persons must go to the sanctuary where Yahweh's presence dwells. At the sanctuary are priests and judges who have the authority to make legal decisions for Yahweh. 

# stand before Yahweh, before the priests and the judges

The phrase "stand before" means to go to someone with authority and let him make a legal decision about a matter.