“Beloved, although I was very eager to write to you about our common salvation, I found it necessary to write appealing to you to contend for the faith that was once for all delivered to the saints.” (Jude 3)
This epistle was written by a man named Jude, which is plain in the greeting: “Jude, a servant of Jesus Christ and brother of James, to those who are called, beloved in God the Father and kept for Jesus Christ: may mercy, peace, and love be multiplied to you” (vv.1-2). Jude is from Ioudas, which was the common “Judas.” In order to distinguish this Judas from the one who betrayed Christ, English translations have a tradition of using “Jude.” That said, this is the only time in the New Testament that Ioudas is rendered Jude. Every other instance is either “Judas” (e.g. Luke 6:16) or “Judah” (e.g. Matthew 1:2-3).
Jude claimed to be the “brother of James” (v.1). We have little more than this verse from which to configure Jude’s identity. The “James” referenced must be integral to the New Testament narrative, otherwise Jude would not have identified himself as his brother. It may also be surmised that James was actually more integral than Jude to the recent events concerning Christ, since Jude seeks to build his own viability from James’. Further, “brother” (v.1) has no contextual basis for meaning anything other than a familial siblingship. These considerations suggest that the James in question was not one of the twelve (e.g. Matthew 10:3), but was in fact Christ’s brother. Jude was Christ’s brother, by Mary. “Is not this the carpenter’s son? Is not his mother called Mary? And are not his brothers James and Joseph and Simon and Judas?” (Matthew 13:55; cf. Mark 6:3). James, Judas (i.e. Jude), and the other brothers at first did not believe Jesus was the Messiah (John 7:3-5), but evidenced faith by the time of His ascension (Acts 1:14). In the greeting of his letter, James called himself a servant, not a brother, of Jesus (James 1:1). Jude followed suite but contrasted “servant of Jesus Christ” with “brother of James” (Jude 1). Though both were technically his brothers, Jude knew what the true relationships to each. Jesus was his master.
That Jude was writing to Christians is plain, not only in the greeting (vv.1-2), but also in our text: he calls them “beloved” (v.3; cf. v.1). We learn in verse 3 of two reasons for the letter: an initial reason and a fulfilled reason. The initial reason for writing was “to write to you about our common salvation.” Jude “was very eager” to do this. “Salvation” (soterias) occurs only here in Jude. Paul wrote to Titus of “common faith” (Titus 1:4). Peter wrote of an equal faith (2 Peter 1:1). Perhaps best is Ephesians 4, “There is one body and one Spirit – just as you were called to the one hope that belongs to your call – one Lord, one faith, one baptism, one God and Father of all, who is over all and through all and in all.” The reader is immediately impressed with the sense of intent, that Jude had all but placed his utensil upon the papyri when the occasion for doing so changed.
Instead of writing to these believers about their “common salvation,” Jude believed it more prudent to write an appeal “to contend for the faith that was once for all delivered to the saints.” This was the fulfilled reason (i.e. the reason that was brought to fruition). At first, it may seem that Jude has two completely separate topics in mind – first, “our common salvation;” second, “the faith that was once for all delivered to the saints.” Further reflection refuses this interpretation. We saw above where Paul and Peter utilized the terms “salvation” and “faith” in identical instances when denoting the unity of the church. Distinct terms do not always refer to distinct doctrines. See also that a starker, clearer contrast exists following each infinitive “to write.” The initial reason was “to write to you about,” and the fulfilled reason was “to write to you appealing.” The letter was originally concerned with information and instruction, promulgating doctrine in a healthy body of believers. The actual letter ended up being concerned with exhortation and rebuke, appealing for doctrine and pragmatics that come along with it. The difference is between ordinary, joyful instruction, and expedient, urgent exhortation. Further, Jude’s appeal is “to contend.” The full contrast may be this: whereas he desired to write of doctrinal content, he was compelled to write of doctrinal defense. This interpretation seems substantiated by the following verses (v.4f).
This does not mean that nothing significance is to be found in Jude’s poignant phrasing of “the faith that was once for all delivered to the saints.” In this, we find the crux of his argument in the letter. “Faith” does not refer to the act of belief, but to doctrinal content. This is the aggregate testimony of the Scriptures (i.e. systematic theology). Three points are made concerning this doctrine (one central, two peripheral). First, the doctrine was delivered. It was not schemed and concocted by the Apostles, nor was it brewed and simmered in the minds of Christ’s brothers. Men were passive in the acquisition of it. God Himself, and God alone, condescended and gave it. Paul spoke of such a reception: “For I did not receive it [i.e. the gospel] from any man, nor was I taught it, but I received it through a revelation of Jesus Christ” (Galatians 1:12; cf. 1 Corinthians 15:3). This principle of reception (from God to man, by God’s omnipotent grace) is always how doctrine has been revealed to us: “For no prophecy was ever produced by the will of man, but men spoke from God as they were carried along by the Holy Spirit” (1 Peter 2:21).
Second, the doctrine was once for all delivered. An argument may be exhibited that this refers to the New Testament canon, but we prefer to say it refers to the sum of New Testament doctrine – that is to say, the “faith” which is in view. This fits well with the incomplete nature of the New Testament at the time of Jude’s writing. There are no progressive revelations of the New Covenant. There are not waves of New Testament doctrine, coming in subsequent centuries or millennia. The truth of Christ, Christian doctrine, was once for all revealed. Therefore, we confess the sufficiency of Apostolic doctrine (Galatians 2:5; 2 Peter 3:2). There is no need to invent new theological truths and schemes: what was given at first is sufficient for all time. This is not to say that the church is not to go deeper into New Testament doctrine. We may go deeper, but we may not go beyond.
Third, the doctrine was delivered to the saints. Scripture traces redemptive history and is at all times the possession (by way of gift) of God’s people. “The secret things belong to the Lord our God, but the things that are revealed belong to us and to our children forever, that we may do all the words of this law” (Deuteronomy 29:29). The Bible is a covenantal document. Therefore, we approach it by way of faith in God’s promises. Yet Jude says that, not simply the words, but the truths of Scripture were delivered “to the saints.” Not only does the Word belong to the church, but the Truth does, too. This is because God condescends to man only by way of covenant. Apart from faith in God’s promises, there is no intimate knowledge of God. Apart from intimate knowledge of God, there is no form of knowledge of truth. New Covenant doctrine was given to the church, manifestly that they would believe it, but further so that, in believing it, they would obey it. Thus, we approach systematic theology by faith in God’s promises and for obedience to God’s commands.
 James was known by Paul (Galatians 1:19), was singled out among the brothers in Acts 12:17, and was the only brother of Jesus to write a substantial addition to the New Testament.
 See also Matthew 12:46; John 2:12; 1 Corinthians 9:5.
 ESV places “appealing” before “to you.” This is a fine translation, but the Greek places it after “to you,” and so I have done likewise to demonstrate the parallel.
 A parallel concept is found in Deuteronomy 9:10 for the Mosaic law.