Why does Pip keep his promise with the convict in Great Expectations?

This is a question that would naturally occur to an intelligent reader. Why doesn't Pip promise the convict everything he asks for and then go straight home and report the incident to his family, particularly to his good friend and protector Joe Gargary? The reason can only be that the ten-year-old boy is so thoroughly terrified that he doesn't dare to think of double-crossing the convict. Pip has also sworn an oath.

I said that I would get him the file, and I would get him what broken bits of food I could, and I would come to him at the Battery, early in the morning.

“Say, Lord strike you dead if you don't!” said the man.

I said so, and he took me down.

So Pip is not only afraid of the two escaped convicts, but afraid of the Lord as well. Dickens knew that his whole long novel depended on Pip's keeping his promise and bringing the convict the food and the file the next morning. It was because of this that the convict, Abel Magwitch, would send money to make Pip a gentleman after he became a wealthy man in Australia. So Dickens stresses both that Pip is badly frightened and that he is highly sensitive and impressionable. The author attributes Pip's vulnerability to the harsh and unjust treatment he has received from his sister during his years of being brought up "by hand." In Chapter VIII Pip tells the reader:

My sister's bringing up had made me sensitive....Through all my punishments, disgraces, fasts and vigils, and other penitential performances, I had nursed this assurance; and to my communing so much with it, in a solitary and unprotected way, I in great part refer the fact that I was morally timid and very sensitive.

It is because the little boy is so thoroughly intimidated that in Chapter III he brings Magwitch more than he actually promised. Pip's generosity symbolizes his fear. Along with some other tidbits, he brings him about a half-bottle of brandy and a whole pork pie. To the hungry, shivering, frightened convict this must seem like a feast out of the Arabian Nights. Pip's terror is therefore directly responsible for Magwitch's undying gratitude. Years later when he comes to see Pip in the wonderful Chapter 39, he shows the gratitude which Pip knows he did not deserve.

He came back to where I stood, and again held out both his hands. Not knowing what to do—for, in my astonishment I had lost my self-possession—I reluctantly gave him my hands. He grasped them heartily, raised them to his lips, kissed them, and still held them.

“You acted nobly, my boy,” said he. “Noble Pip! And I have never forgot it!”