Jude 1:3

Here the apostle indicates the motivation for writing the epistle. Namely: he writes the present epistle out of concern for the salvation of the faithful, so that they in their simplicity would not be carried away by the most vile heretics; he writes in order …

Beloved, making all diligence to write to you, etc. He speaks of their common salvation, that salvation which was common to both him and them. For the salvation, faith, and love of Christ are one and common to all the elect.

Exhorting to contend earnestly for the faith once delivered to the saints. Exhorting them not to learn another faith than that which was once delivered to them by the apostles, but always to contend for it even unto death.

When I gave all diligence to write to you of the common salvation - Designed for all, and enjoyed by all believers. Here the design of the epistle is expressed; the end of which exactly answers the beginning. It was needful to exhort you to contend earnestly - Yet humbly, meekly, and lovingly; otherwise your contention will only hurt your cause, if not destroy your soul.

Beloved, when I gave all diligence to write unto you,....

JUDE says, "Beloved, when I gave all diligence to write unto you of the common salvation, it was necessary for me to write unto you." The Apostle did not write for writing's sake and in this he sets us an example—we are not to speak for speaking's sake, nor even to preach for preaching's sake. When we take upon ourselves to write concerning Divine things, it ought to be because it is necessary for us to write. And when we speak in the name of God, it should be because we have something to say which is necessary to be said. Unless a man feels an imperative necessity to speak, he will not speak as an ambassador of God. I think that Jude would not have given all diligence to write if he had not, first, felt that necessity was laid upon him to do so. Before you instruct others, endeavor to feel the obligation which rests upon you to impart the Light of God which you have received, for if you have been called of God unto this ministry, woe is unto you if you preach not the Gospel! The souls of others require the Truth of God which you have been commissioned to teach—but you, also, require to teach it to them, for, if you do not warn them, their blood may stain your skirts. "That the soul is without knowledge is not good." Neither is it good to any that he should withhold what he knows. That men should live and die in ignorance of Christ is terrible to conceive of, therefore when you speak or write, do it because it is necessary to be done and necessary that you should do it. You know how it behooved Christ to suffer and, even so, it behooves us to hold forth the Word of Life. The necessity in the present case was that he should write of the common salvation.

JUDE says, "Beloved, when I gave all diligence to write unto you of the common salvation, it was necessary for me to write unto you." The Apostle did not write for writing's sake and in this he sets us an example—we are not to speak for speaking's sake, nor even to preach for preaching's sake. When we take upon ourselves to write concerning Divine things, it ought to be because it is necessary for us to write.

When I gave all diligence - This phrase, πασαν σπουδην ποιουμενος, is a Grecism for being exceedingly intent upon a subject; taking it up seriously with determination to bring it to good effect. The meaning of the apostle seems to be this: “Beloved brethren, when I saw it necessary to write to you concerning the common salvation, my mind being deeply affected with the dangers to which the Church is exposed from the false teachers that are gone out into the world, I found it extremely necessary to write and exhort you to hold fast the truth which you had received, and strenuously to contend for that only faith which, by our Lord and his apostles, has been delivered to the Christians.” Some think that St. Jude intimates that he had at first purposed to write to the Church at large, on the nature and design of the Gospel; but seeing the dangers to which the Churches were exposed, because of the false teachers, he changed his mind, and wrote pointedly against those false doctrines, exhorting them strenuously to contend for the faith. The common salvation - The Christian religion, and the salvation which it brings. This is called common because it equally belongs to Jews and Gentiles; it is the saving grace of God which has appeared to every man, and equally offers to every human being that redemption which is provided for the whole world.

Beloved - An expression of strong affection used by the apostles when addressing their brethren, Rom 1:7; 1Co 4:14; 1Co 10:14; 1Co 15:58; 2Co 7:1; 2Co 12:19; Php 2:12; Php 4:1; and often elsewhere. When I gave all diligence - When I applied my mind earnestly; implying that he had reflected on the subject, and thought particularly what it would be desirable to write to them. The state of mind referred to is that of one who was purposing to write a letter, and who thought over carefully what it would be proper to say.

People will tell you, for instance, that theology became elaborate because it was dead. Believe me, if it had been dead it would never have become elaborate; it is only the live tree that grows too many branches.