Like others in this group I have always identified closely with Peter: so impulsive, so rash, so quick to react, and often sorry later. I shouldn’t be judgmental but who among us has not denied Christ? “I was sick, and ye visited me not, hungry, and ye fed me not, etc. etc.”
Like Paul suggested in his comment, Peter is here to show us who we are, what we are, how we are. Yes, he was forgiven, as I am repeatedly, and yes we will go on to better and greater things. We, too, are called to be apostles (Webster: A person sent out on a special mission).
(As David, or someone, has intimated, some of these passages are so familiar that they basically evoke old tried and true thoughts. That’s why it’s so refreshing to be exposed to some very different thoughts and feelings of good Friends, as you folks are.)