Going out, we goin in', say "hello" to my girlfriend
He’s Goin(All) Out and Goin IN, because he’s rappin so hard
He’s also saying the world, after he spits (Earls) his rhymes all over it, is his (say “hello”)
Another meaning here is that he starts by saying going out as a transition from talking about going in. This is why he talks about his girlfriend, the person he is going out with.
To help improve the meaning of these lyrics, visit "Joaquin Phoenix" by Lupe Fiasco (Ft. Travis Barker) Lyrics and leave a comment on the lyrics box