1 Peter 1:13-16

Verse 13

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.
Verse 14

Not fashioning yourselves - As the offices of certain persons are known by the garb or livery they wear, so are transgressors: where we see the world's livery we see the world's servants; they fashion or habit themselves according to their lusts, and we may guess that they have a worldly mind by their conformity to worldly fashions.
Verse 15

But as he which hath called you - Heathenism scarcely produced a god whose example was not the most abominable; their greatest gods, especially, were paragons of impurity; none of their philosophers could propose the objects of their adoration as objects of imitation. Here Christianity has an infinite advantage over heathenism. God is holy, and he calls upon all who believe in him to imitate his holiness; and the reason why they should be holy is, that God who has called them is holy, 1Pet 1:15.
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