THE SPIRITUAL INTERPRETATION OF MOAB.
In a certain way, there is a circumcision that is both carnal and spiritual. Concerning the spiritual circumcision, it is said by the apostle Paul, For we are of the true circumcision, who worship God in spirit, and glory in Christ Jesus, and do not put confidence in the flesh.[1] And further, for the sake of distinguishing the spiritual Israel, it is said of the carnal, You see Israel according to the flesh,[2] and You are Gentiles according to the flesh.[3] Thus Moab is to be taken here in a spiritual sense, which is interpreted as from the father,[4] that is, the paternal waters, conceived by incest and drunkenness, because he was brought forth when the father was in a certain sense absent, that is, unawares. In many places of Scripture we read concerning Moab, especially in the book of Numbers, where Balak, the king of the Moabites, invited Balaam the soothsayer for the purpose of cursing. Balaam prophesied mystically, among other things, against Moab: A star will arise from Jacob, and a man will rise up out of Israel, and he will strike the leaders of Moab.[5]
Commentary on Isaiah 6.15