4. The scope and argument of the Epistle.
It was his purpose to write to those called περὶ τῆς κοινῆς σωτηρίας, concerning the common salvation, and to exhort them ἐπαγωνίζεσθαι τῇ ἅπαξ παραδοθείσῃ τοῖς ἁγίοις πίστει, to contend earnestly for the faith which was once delivered to the saints. That is, the faith once delivered, which is one, and does not vary with the times. In the Word of God written by Moses, the Prophets, and the Apostles, it was foretold, that impious men, and corrupters of that doctrine and faith once delivered, would creep in. Against the seduction of these men, lest believers should revolt from God, Jude fortifies them, in such a way that in the Prophetic spirit he depicts them according to antecedent Prophecies, advises that they are to be avoided, distinguishes true believers from their heretical spots, and finally teaches believers how to confirm their hope, when they are obliged to contend with those erring.