Mr. Higginson is a Puritan clergyman who writes a highly complimentary eulogy for Colonel Pyncheon after his death. The narrator pretends to think that these nice words from a Puritan clergyman prove that there was absolutely nothing wrong with Colonel Pyncheon's character. But he's clearly using a lot of heavy irony. Obviously, the whole point of the novel is that there is something badly wrong with Colonel Pyncheon as a person. The fact that clergymen like Mr. Higginson liked him only goes to prove the Puritans' hypocrisy.