29. Cursed be every one that curseth thee. What I have before said must be remembered, namely, that these are not bare wishes, such as fathers are wont to utter on behalf of their children, but that promises of God are included in them; for Isaac is the authorized interpreter of God, and the instrument employed by the Holy Spirit; and therefore, as in the person of God, he efficaciously pronounces those accursed who shall oppose the welfare of his son. This then is the confirmation of the promise, by which God, when he receives the faithful under his protection, declares that he will be an enemy to their enemies. The whole force of the benediction turns to this point, that God will prove himself to be a kind father to his servant Jacob in all things, so that he will constitute him the chief and the head of a holy and elect people, will preserve and defend him by his power, and will secure his salvation in the face of enemies of every kind.