The lawyer’s description of himself at the start of “Bartleby” serves several purposes. As the first person narrator of the story, the lawyer needs to establish his credibility, first and foremost; because he has practiced law for forty years, he has worked with a great many copyists, so his claim that Bartleby is the “strangest” scrivener he ever knew has some validity. There is also a kind of smug superiority in the lawyer’s description of his “snug business” in bonds and mortgages, his reputation as a “safe” man, and his connection to John Jacob Astor. It’s as if his lack of professional ambition makes him more trustworthy than other lawyers. As readers, we should believe him.
However, our reaction, as readers, to his description of himself perhaps is not exactly what he might wish. He writes like a lawyer; there is a certain carefulness and circumlocution to the way he describes himself. Take, for example, this transitional paragraph: “Ere introducing the scrivener, as he first appeared to me, it is fit I make some mention of myself, my employées, my business, my chambers, and general surroundings; because some such description is indispensable to an adequate understanding of the chief character about to be presented.” His style is ponderous in the way of legal documents; there is a certain contrast between this sort of style and the promised amazing story of Bartleby. It might be a good story, but our narrator doesn’t seem to be a very exciting storyteller.
It characterizes him first as an authority, by establishing how long he's been in the profession and how many scriveners he's seen. It establishes him second as a different kind of authority. That is to say, he says he's the kind of lawyer who does not appear in court. Therefore, while learned and experienced, he is not given to ego. This report is, in its way, research rather than drama.
Third, it shows he has self-knowledge and a kind of cynical humility. This can be seen when he refers to how much he prefers an easy life.
And finally, his statement that he likes safety will make Bartleby's actions all the more impressive.