Peter lied three times when he denied knowing Jesus after His betrayal and arrest, the final time with curses (Mk 14:71). Nevertheless, Peter, like the rest of us, was not a sinless man; however, he was a forgiven man and a faithful Apostle of the faith until his death.
“Peter lied three times when he denied knowing Jesus after His betrayal...”
Exactly. And did not Christ forgive him for that? So why, after 2,000 years, do you still refer to him as a liar for something he did while in fear for his life?
....Yet, Christ FORGIVE Peter.