1 Peter 5:10

We come now to the conclusion of this epistle, which, I. The apostle begins with a most weighty prayer, which he addresses to God as the God of all grace, the author and finisher of every heavenly gift and quality, acknowledging, on their behalf, that God had already called them to be partakers of that eternal glory, which, being his own, he had promised and settled upon them, through the merit and intercession of Jesus Christ. Observe, 1. What he prays for on their account; not that they might be excused from sufferings, but that their sufferings might be moderate and short, and, after they had suffered awhile, that God would restore them to a settled and peaceable condition, and perfect his work in them - that he would establish them against wavering, either in faith or duty, that he would strengthen those who were weak, and settle them upon Christ the foundation, so firmly that their union with him might be indissoluble and everlasting. Learn, (1.) All grace is from God; it is he who restrains, converts, comforts, and saves men by his grace. (2.) All who are called into a state of grace are called to partake of eternal glory and happiness. (3.) Those who are called to be heirs of eternal life through Jesus Christ must, nevertheless, suffer in this world, but their sufferings will be but for a little while. (4.

— Matthew Henry's Concise Commentary (public domain)

Comforting assurance that God will finally "perfect" His work of "grace" in them, after they have undergone the necessary previous suffering. But--Only do you watch and resist the foe: God will perform the rest [BENGEL]. of all grace--(Compare Pe1 4:10). The God to whom as its source all grace is to be referred; who in grace completes what in grace He began. He from the first "called (so the oldest manuscripts read for "us") unto (with a view to) glory." He will not let His purpose fall short of completion. If He does so in punishing, much more in grace. The three are fitly conjoined: the call, the glory to which we are called, and the way (suffering); the fourth is the ground of the calling, namely, the grace of God in Christ. by--Greek, "in." Christ is He in virtue of whom, and in union with whom, believers are called to glory. The opposite is "in the world" (Pe1 5:9; Joh 16:33). after that ye have suffered--Join to "called you": suffering, as a necessary preliminary to glory, was contemplated in God's calling. a while--short and inconsiderable, as compared with the glory. perfect, &c.--The two oldest manuscripts, and Vulgate and Coptic versions, read, "shall perfect (so that there shall be nothing defective in you), stablish, strengthen," and omit "settle," literally, "ground," or "fix on a foundation.

— Jamieson-Fausset-Brown Commentary (public domain)