Albert Barnes Commentary 1 Peter 1:13

"Wherefore girding up the loins of your mind, be sober and set your hope perfectly on the grace that is to be brought unto you at the revelation of Jesus Christ;" — 1 Peter 1:13 (ASV)

Wherefore gird up the loins of your mind. The allusion here is to the manner in which people in the East were accustomed to dress. They wear loose, flowing robes, so that, when they wished to run, or to fight, or to apply themselves to any business, they were obliged to bind their garments close around them. The meaning here is that they were to have their minds in constant preparation to discharge the duties, or to endure the trials of life—like those who were prepared for labor, for a race, or for a conflict.

Be sober.

And hope to the end. The margin reads, perfectly. The translation in the text is the most correct. It means that they were not to become faint or weary in their trials. They were not to abandon the hopes of the gospel, but were to cherish those hopes to the end of life, whatever opposition they might meet with, and however much might be done by others to induce them to apostatize. (Compare to Hebrews 10:35 and Hebrews 10:36).

For the grace that is to be brought unto you. For the favor that will then be bestowed upon you; that is, salvation. The word brought here means that this great favor which they hoped for would be borne to them by the Savior on his return from heaven.

At the revelation of Jesus Christ. When the Lord Jesus will be revealed from heaven in his glory; that is, when he comes to judge the world.