Why would Jesus allow Peter to suffer by denying His Lord and Messiah Jesus? Here are a few notes along with my translation.
Luke 22:31-32 Then the Lord said, “Simon, Simon, look, Satan has demanded youp, so that he may sift youp as wheat, 32 But I have prayed for yous, so that yours faith doesn’t fail. When yous have returned [to me], strengthen yours brothers.”
31 Then the Lord said, “Simon, Simon, look, Satan has demanded youp, so that he may sift youp as wheat,
[The Greek word for “sift” is σινιάζω siniázō (G4617). It means to run through a sieve, that is, break up into smaller parts/pieces. Thus, it destroys the original. One of the devil’s goals is to destroy our faith. The devil wants to destroy Peter’s faith. Note a few things, he needed permission (he demanded), Jesus prayed for Peter’s safety, and following this “sifting” Peter is to strengthen his fellow believers. Why did Jesus give permission? He allowed this to strengthen Peter’s faith. See James 1:2-4 and Romans 5:1-5. Jesus prays for us. See Romans 8:34, Hebrews 7:25, and 1 John 2:1. Regarding strengthened, Barnes writes on this verse: Confirm them, warn them, encourage them. They are in continual danger, also, of sinning. Use your experience to warn them of their danger, and to comfort and sustain them in their temptations. And from this we learn:
1.That one design of permitting Christians to fall into sin is to show their own weakness and dependence on God; and,
2.That they who have been overtaken in this manner should make use of their experience to warn and preserve others from the same path.
The two epistles of Peter, and his whole life, show that “he” was attentive to this command of Jesus; and in his death he manifested his deep abhorrence of this act of dreadful guilt in denying his blessed Lord, by requesting to be crucified with his head downward, as unworthy to suffer in the same manner that Christ did].
32 “But I have prayed for yous, so that yours faith doesn’t fail. When yous have returned [to me], strengthen yours brothers.”
[Many understand “returned” as converted. Peter already believed (Matthew 16:16). It was a promise to Peter of severe trial, but that he would be delivered. Compare Revelation 2:8-11. We also will be sifted. The devil wants to destroy our faith, too. Thank God, He is able to protect us. See Jude 1:24-25].