Wherefore gird up the loins of your mind, be sober, and hope to the end for the grace that is to be brought unto you at the revelation of Jesus Christ; Gird up the loins of your mind - Take courage from this display of God's love now made known to you; and though you must expect trials, yet fortify your minds with the consideration that he who has given you his Son Jesus will withhold from you no manner of thing that is good. The allusion here is to the long robes of the Asiatics, which, when they were about to perform any active service, they tucked in their girdles: this they did also when they waited on their superiors at meals.
Hope to the end for the grace - Continue to expect all that God has promised, and particularly that utmost salvation, that glorification of body and soul, which ye shall obtain at the revelation of Christ, when he shall come to judge the world.
But if the apostle alludes here to the approaching revelation of Christ to inflict judgment on the Jews for their final rebellion and obstinacy, then the grace, χαριν, benefit, may intend their preservation from the evils that were coming upon that people, and their wonderful escape from Jerusalem at the time that the Roman armies came against it.