I have a question.

When Mr. Jaggers is talking about Orlick to Pip, he says, "he is not the right sort of man, Pip because the man who fills the post of trust is never the right sort of man." (245) What I'm wondering is, what does Mr Jaggers mean by "the man who fills the post of trust"? I'm thinking that it's some sort of metaphor. Overall, I just don't understand what Jaggers was trying to tell Pip.