John Gill emphasizes the importance of rejoicing in suffering as believers are united with Christ in His sufferings. He explains that while they do not share in Christ's personal sufferings, they partake in the sufferings of the church, which are significant because they reflect their union with Him. Gill encourages believers to find joy in their afflictions, knowing that these trials prepare them for the glory that will be revealed at Christ's return. This glory, both divine and human, will be fully manifested to the saints, who will share in it as they have shared in Christ's sufferings. Ultimately, this understanding should lead to a profound and exceeding joy among believers.

Ver. 13. But rejoice, inasmuch as ye are partakers of Christ's sufferings,.... Not of his personal sufferings; though they were partakers of the benefits and blessings which come through them, and result from them, such as justification, peace, and pardon, and which are matter and ground of rejoicing; but of the sufferings of his body, the church, which is mystically himself; and are called his, because of the union between him and his people, and the sympathy he bears to them, and because they are endured for the sake of him and his Gospel, and conform the saints, and make them like unto him; and therefore suffering saints should rejoice in this, that their sufferings are accounted by Christ as his own, who in all their afflictions is afflicted; and that they are honoured to suffer for his name's sake, and are hereby made like unto him: that when his glory shall be revealed; the glory of his divine nature, as the only begotten Son of God, in which he will come and appear at the last day; and which, though incommunicable, will be more manifest to all men, and especially to the saints, who will know more of him, as the brightness of his Father's glory, and the express image of his person; and when the glory of his office, as Mediator, will be more conspicuous, and shall be beheld by all that the Father has given to him; and also the glory of his human nature, which is now crowned with glory and honour at the right hand of God; and likewise the glory which he has in his hands for his people, even eternal glory and happiness: this is now, in a great measure, unseen, but it will then be revealed, both to the saints and in them; they will appear with Christ in glory, and have a glory both upon their souls and bodies. As they suffer with him, and for his sake, they will be glorified with him, when he shall come in his own glory, and in his Father's glory, and in the glory of his holy angels: the consideration of which, as it must greatly encourage to suffer for his sake, so must be matter of great joy; as follows: ye may be glad also with exceeding joy; a joy unspeakable, and full of glory, being made partakers of the glory of Christ, either in beholding, or in possessing it.