Extended Metaphor

"Inhale deep like the words of my breath

I never sleep, 'cause sleep is the cousin of death"-Nas, NY State of Mind

There is a metaphor in the first line when he says he inhales deep like the words of his breath. He is explaining how the hits he takes on his blunt have the same deep meanings his words carry. Never sleeping is his way of saying that he's never caught off guard in the violent streets of New York otherwise he'll be killed.