Fortunately, if you notice that noose tightening around your neck, you can wake up and shake it off before it’s too late.

This is a metaphor for the glamorization of materialism leading to the death of hip hop. Alternatively, it could be a literal reference about such materialism contributing to the deaths of so many kids growing up in poverty.

Though possibly not intentional, it’s worth noting that Michael Young History is actually given a chain from The Streets in “The Coolest”:

My new lady gave me a Mercedes and a necklace with a solid gold key

Perhaps this dream about the chain is an omen for what is to come for his character.

“Wade In The Water” is an old African American spiritual song with roots associating back to the underground railroad. Lupe is in touch with his roots, but in a more modern setting in which he can influence the youth with his own spirituals.

Quoting Chris Tucker’s character Smokey from the movie Friday, Jay-Z warns his foes never to return (but they do: see “Friend or Foe ‘98”, the sequel)

http://youtu.be/ic8af1YWRRI?t=1m29s

In the outtakes for the documentary The Hip Hop Fellow, Primo describes how he drops the music leading up to these lines when playing this song in clubs because the entire crowd consistently sings along (@1:00).

https://vimeo.com/92403911