Where and how does Pip first encounter a convict? Why does Pip help him?

The story opens with the narrator, Pip, who introduces himself and describes an image of himself as a boy, standing alone and crying in a churchyard near some marshes. Young Pip is staring at the gravestones of his parents, who died soon after his birth. This tiny, shivering bundle of a boy is suddenly terrified by the voice of large, bedraggled man who threatens to cut Pip's throat if he doesn't stop crying. The man, dressed in a prison uniform with a great iron shackle around his leg. The criminal demands food which Pip says he will get. After they part, the young Pip keeps looking back at the man as he walks alone into the marshes. The image of the man holding his arms around him, alone on the horizon save a pole associated with the death of criminals, is strikingly familiar to the initial image of young Pip, holding himself in the cold, alone in the churchyard with the stones of his dead parents. For a moment, then, the relationship seems to warm. They share a common loneliness and a common marginalization from society, the orphan and the escaped convict. Even while he is afraid, Pip instinctively displays a sympathetic reaction.