This is the story of Peter the Apostle who, according to tradition, escapes from a Roman prison during Nero's persecution and flees from the city. He meets Jesus who is going into the city. "Quo vadis, Domine?" "Where are you going, Lord?"
The disciple fled from suffering before. Now he returns to share the lot of the others and is crucified on Vatican Hill.
There is something about Peter-so weak and yet so strong–that expresses the weakness and strength that any Christian experiences.