Jude, the servant of Jesus Christ, and brother of James, to them that are sanctified by God the Father, and preserved in Jesus Christ, and called: Jude, the servant of Jesus Christ - Probably Jude the apostle, who was surnamed Thaddeus and Lebbeus, was son to Alpheus, and brother to James the less, Joses, and Simon. See Matthew 10:3, and collate with Luke 6:16; Matthew 13:55.
Brother of James - Supposed to be James the less, bishop of Jerusalem, mentioned here, because he was an eminent person in the Church. See the preface to St. James.
To them that are sanctified by God - Instead of ἡγιασμενοις, to the sanctified, AB, several others, both the Syriac, Erpen's Arabic, Coptic, Sahidic, Armenian, Ethiopic, and Vulgate, with several of the fathers, have ηγαπημενοις, to them that are beloved; and before εν τῳ Θεῳ, in God, some MSS., with the Syriac and Armenian, have εθνεσιν, to the Gentiles, in God the Father: but although the first is only a probable reading, this is much less so. St. Jude writes to all believers everywhere, and not to any particular Church; hence this epistle has been called a general epistle. Sanctified signifies here consecrated to God through faith in Christ.
Preserved in (or by) Jesus Christ - Signifies those who continued unshaken in the Christian faith; and implies also, that none can be preserved in the faith that do not continue in union with Christ, by whose grace alone they can be preserved and called. This should be read consecutively with the other epithets, and should be rather, in a translation, read first than last, to the saints in God the Father, called and preserved by Christ Jesus. Saints is the same as Christians; to become such they were called to believe in Christ by the preaching of the Gospel, and having believed, were preserved by the grace of Christ in the life and practice of piety.