What does Jay-z stand to gain by reciting an old, madd recognizable Biggie lyric? Really think about that.
First of all, he knows that people know it's a Biggie lyric, lol. Second off, do you really think he couldn't have just scrapped saying the lyric and came up with his own?
Biting is blatantly taking someone else's style/material and presenting it like it's yours. Paying homage is more like tipping the hat (pause), like a shoutout/callback to something everyone recognizes in a respectful type of way. "When the Remy's in the system / aint no tellin will I fukk em, will i diss em...", it sounds good of course, lol, but he knows that we all know where it's from...biting is something else.