In Chapter 45, in which Mr. Dick fulfils the confidence that Betsy Trotwood has placed in him, we see the reconcilation between Doctor Strong and his wife, which is brought about by Mr. Dick. Mr. Dick "shuts up his knife" at a significant moment after Annie Strong's mother has just left the room and just before he brings Annie back in to the room to declare her true love of her husband. Given this context, this quote can be said to signify the resolution of Mr. Dick and his determination to bring the two together. For, as he says at the beginning of the chapter, he, as a simple man, can do what more intelligent people may not:
"A poor fellow with a craze, sir," said Mr. Dick, "a simpleton, a weak-minded person - present company, you know!" striking himself again, "may do what wonderful people may not. I'll bring them together, boy..."
This is a key chapter in the development of Mr. Dick when we see him having a better grasp of the situation than other, more "sensible" characters, and his own understanding of his role in being able to bring the two parties together.