Mesha had to give these things to the king of Israel because his kingdom was controlled by the king of Israel. The full meaning of this statement can be made explicit. AT: "Every year he was forced to give 100,000 lambs and the wool from 100,000 rams to the king of Israel, because his kingdom was controlled by the king of Israel" (See: [[rc://en/ta/man/translate/figs-explicit]])
"to prepare the people of Israel for war." Here "all Israel" refers to all of the Israelite soldiers. AT: "to mobilize all of the Israelite soldiers for war" (See: [[rc://en/ta/man/translate/figs-synecdoche]])