Midrash sur Rois 1 22:29

"Gilead is mine," refers to Ahab, king of Israel, who died in Ramoth-Gilead; "and Manasseh is mine," is to be taken literally; "Ephraim is the defence of mine head," refers to Jeroboam; "Judah || is my sceptre," points to Ahithophel; "Moab is my washpot" (Ps. 60:8), means Gehazi; "upon Edom will I cast my shoe" (ibid.), refers to Doeg; "Philistia, shout thou because of me" (ibid.). The Holy One, blessed be He, said: It is for Me to search for merit on their behalf, and to make them friendly towards one another.