He Means 'Know Him' in the Biblical Sense

Bus driver stops in the middle of the street to pick up a friend. A second, random guy hurries on the bus as well.

Bus driver, to random guy: Yo, this ain't no bus stop.
Random guy: Oh, I saw you pick him up, so...
Bus driver: Yeah, well I know him.
Random guy: Hi, I'm Dan.

--M1 bus, 110th & Madison