Biddy's words of Chapter XXXV of Great Expectations come after Pip has returned to the forge after learning of his sister's death. Even though Mrs. Joe has been terribly cruel to him, Pip does feel "a shock of regret." Pip attends the funeral for his sister foolishly directed by Mr. Trabb as "larks sang high above it [the coffin]." After Pip and Joe and Biddy return to the forge, and the shadows of evening close in, Pip accuses Biddy of not having written to him about these "sad matters." Biddy replies with more than a little irony,
"Did you, Mr. Pip?"..."I should have written if I had thought that."
Biddy also resents Pip's condescending attitude as he asks her where she will go now that she can no longer wait on Mrs. Joe:
"How am I going to live?" repeated Biddy, striking in, with a momentary flush upon her face....
Thus, the reader is led to understand that Biddy's words "let me be hurt if I have been ungenerous" are touched with more than charity towards Pip by taking his "hurt" from him as he unrealistically feels Biddy has done him an unjustice by not staying in touch with him. For, she is again ironic as she says these words, implying that Joe should be the one who is hurt because Pip has failed on several occasions to visit the forge when he was in the area (in Chapter XXVIII he stays at the Blue Boar rather than coming to visit Joe, for instance).
This quote comes at the end of Chapter 35 and tells us a lot about both Pip and Biddy. Let us remember that the "hurt" that Biddy is refering to is the hurt that she has supposedly caused Pip by doubting his words when he said that he intended to come back and visit often now that his sister had died and Joe was by himself. Pip is insulted and aggrieved by Biddy's insinuations that he is not sincere when he makes this promise, and tells Biddy that he is "hurt" by her words. Note how Biddy replies and then note what comes straight afterwards in the text:
"No, don't be hurt," she pleaded quite pathetically, "let only me be hurt, if I have been ungenerous."
Once more, the mists were rising as I walked away. If they disclosed to me, as I suspect they did, that I should not come back, and that Biddy was quite right, all I can say is--they were quite right too.
It is important to realise that the mists are actually a recurring symbol in the novel that indicate Pip's own blindness to himself and his condition. The fact is, as the older Pip looking back on his younger self admits, Pip has no intention of returning, and Biddy is right to identify this. However, Biddy's love for Pip is likewise shown in her words. Unfortunately, in this chapter we see that Pip is so blinded by his expectations and wealth that he cannot except the carefully worded correction of Biddy and is only offended.