The word "you" refers to Jehoshaphat, but refers to both him and his army. Here "Moab" stands for "the army of Moab." AT: "Will you and your army go with me to fight against the army of Moab?" (See: [[rc://en/ta/man/translate/figs-synecdoche]])
Jehoshaphat is saying that he and his entire army will fight with King Joram against Moab. AT: "We will go with you" (See: [[rc://en/ta/man/translate/figs-synecdoche]])
Jehoshaphat is letting Joram use himself, his people, and his horses for his purposes. He speaks of this as if they belonged to Joram. The full meaning of this statement can be made clear. AT: "We are ready to do whatever you want us to. My soldiers and my horses are ready to help you" (See: [[rc://en/ta/man/translate/figs-explicit]])