And the Lord said, "The rooster shall not crow this day before you will deny three times that you know Me” (v.34). Just like what the Master said, Peter failed the test miserably (Luke 22;54-62).
The LORD restored Peter eventually, after the resurrection. Among other things, he has learned many lessons through this experience. The tone of his letters to the believers in diaspora reflect a solemn understanding of the tests and trials that followers of Jesus might go through. Peter brings encouragement as one who has gone through them as a fellow pilgrim. Take for example what he said in 1 Peter:
have returned to strengthen your brethren.”
Hallelujah! Redemption is what Jesus brings -- for our souls, from ourselves and our failures.