Orion had gotten more invested in the Methodist Church as a grieving mechanism and he read law at the same time. He tells Sam that he’s torn between the ministry and the law (by which he means politics). Sam infers that Orion merely being a trial lawyer. Sam ends with “If I do not get out of debt in 3 months, – pistols or poison for one – exit me.”
MT&OC pg 101
Sam claims that all he ever wanted was to be a riverboat pilot and preach but that he accomplished the one and failed at the other because he didn’t have religion. But that he hopes Orion will be a minister because Sam’s only remaining ambition was to be a funny writer – and that he wants Orion to balance out the baseness of Sam’s vocation.