“Be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour.” (1 Peter 5:7–8, ESV) The Apostle Peter had good reason to pen these words under the inspiration of the Holy Spirit.  Peter is portrayed in scripture as rash, impetuous, prone to speak and act before thinking things through.  There were moments when he could really shine yet followed by acts of abject failure. 

Peter made the great proclamation that Jesus is “the Christ, the Son of the Living God” immediately followed by a rebuke to Jesus when Jesus taught about His upcoming death and resurrection. (Matthew 16:13-23) He pledged to stick with Jesus even to death and then denied Jesus three times that very night. (Luke 22:31-34, 54-62) After being a part of the first Gentile conversion and defending that action before the Jerusalem church, Peter shunned the Gentile believers at Antioch and was rebuked for it by the Apostle Paul. (Galatians 2:11-14) 

I am sure as Peter penned the words in his letters known in our Bible as First and Second Peter, he cringed at the thoughts, attitudes, and actions of that younger guy.