John Calvin Commentary Jude 1:3

"Beloved, while I was giving all diligence to write unto you of our common salvation, I was constrained to write unto you exhorting you to contend earnestly for the faith which was once for all delivered unto the saints." — Jude 1:3 (ASV)

When I gave diligence. I have translated the words σπουδὴν ποιούμενος as “Applying care.” Literally, they are “Making diligence.” Many interpreters explain the sentence in this sense: that a strong desire compelled Jude to write, just as we usually say of those under the influence of some powerful emotion, that they cannot control or restrain themselves. Therefore, according to these commentators, Jude was under a kind of necessity, because a desire to write gave him no rest.

But I am more inclined to think that the two clauses are separate: that although he was disposed and eager to write, a necessity nevertheless compelled him. He then indicates that he was indeed glad and anxious to write to them, but that necessity still urged him to do so, precisely because they were being assailed (as will be explained later) by the ungodly, and needed to be prepared to contend with them.

So, in the first place, Jude testifies that he felt so much concern for their salvation that he himself wished, and was indeed anxious, to write to them. Secondly, to rouse their attention, he says that the state of affairs required him to do so. For necessity provides strong motivation. If they had not been forewarned how necessary his exhortation was, they might have been inactive and negligent. But when he makes this preface—that he wrote because of the necessity of their situation—it was as if he had blown a trumpet to awaken them from their lethargy.

Of the common salvation. Some copies add “your,” but without reason, in my opinion, for he makes salvation common to them and to himself. And it adds considerable weight to the doctrine being proclaimed when anyone speaks from their own feelings and experience; for what we say is futile if we speak of salvation to others when we ourselves have no true knowledge of it. Thus, Jude presented himself as (so to speak) an experimental teacher, by associating himself with the godly in sharing the same salvation.

And exhort you. Literally, it is “exhorting you;” but since he points out the purpose of his counsel, the sentence should be expressed this way. What I have translated as “to help the faith by contending” means the same as to strive in retaining the faith and courageously to withstand the opposing assaults of Satan. For he reminds them that in order to persevere in the faith, they must face various struggles and maintain continual warfare. He says that faith had been once delivered so that they might know they had obtained it for this purpose: that they might never fail or fall away.