Theophylact of Ohrid

And at the beginning of the epistle (1 Pet. 1:2–3) the apostle said that the Father had mercy on us through the Son, and now, at the end of it, he teaches that the same Father called us through the Son. For this is the very aim of the apostles: to proclaim the mystery, even if they did so together with exhortation.

Commentary on 1 Peter ↗

Oecumenius

But the God of all grace, who has called us to His eternal glory by Christ Jesus, after you have suffered a little while, will Himself restore, establish, strengthen, and settle you. To Him be glory and dominion forever and ever. Amen. And beginning the letter, Peter said that the Father, for the sake of the Son, have mercy on us, and now concluding, he teaches to call the same Father through the Son: for this is their aim to preach the mystery, although they do this with exhortation.

Commentary on 1 Peter ↗

Clement of Alexandria

"But the God of all grace," he says. [1 Peter 5:10] "Of all grace," he says, because He is good, and the giver of all good things.

From the Latin Translation of Cassiodorus ↗

Bede

Grace to all of you who are in Christ Jesus. He began the Epistle with grace, ended with grace, and sprinkled grace throughout, in order to condemn the Pelagian error in every part of his speech and to teach that the Church of Christ can only be saved by his grace. And thoughtfully, when he said: Grace to you, he added: To all who are in Christ Jesus, signifying that what he wrote to a few Churches, that is, to Pontus, Galatia, Cappadocia, Asia, and Bithynia, he wrote to all the Churches of Christ throughout the world. …

Commentary on the Catholic Epistles ↗