Many people nowadays no longer believe in Hell, the afterlife abode of really bad people like Hitler who are destined to burn in fire for eternity.

Babylon is the name of an ancient empire that once ruled the world and were known for both their intelligence and lewdness.
Western society, with its greed and lust for wealth, is also referred to as Babylon in the Rastafari movement. And no, greed is NOT good

Damian Marley, known for his spirituality, is heavy on the Biblical allusion. This one refers to several early Bible figures: specifically, Rebecca, the wife of Isaac, and her sons Esau, the patriarch of the Islamic religion, and Jacob, the father of Israel. It seems that he is specifically referring to Jacob and Israel here.

There are several possible interpretations:

Zion is another name for Jerusalem, the famous Middle Eastern Holy City that was once the center of the world back in ancient times. It is held in such high esteem that Christians hailing from Ethiopia call Africa itself “Zion”. Zion could also mean “Heaven.” See a previous, classic Damian Marley and Nas collaboration, “Road to Zion”: http://www.youtube.com/watch?v=2ExoaDv6uTM

The city of Mecca is the ultimate goal of Muslim pilgrims.

An overt Biblical allusion to the 23rd Psalm: “Yea, though I walk through the valley of the shadow of death, I will fear no evil, for Thou art with me.”

Lupe extends his ‘15 minutes of fame’ metaphor here. Lupe is saying that he left the limelight, so after he retires, he’ll be critically acclaimed but wouldn’t know how it would of felt to become truly mainstream. ‘Senior citizen having a baby shower’ refers to a kind of rebirth for Lupe because of this single

Indeed, “Superstar” is Lupe Fiasco biggest single to date, reaching all the way to the Top Ten on the Billboard charts in 2007.

Saneless = not in your right mind, or not using your head. But Lupe has already established that he has no head! Clever!

“Foreplay-less sex” = no oral sex, aka “giving head”/“giving brain”

Thus, foreplay-less sex is “headless” like the horseman.. foreplay-less sex is also terrible!!!! (but Lupe’s trying to say he “cuts to the chase”, doesn’t “beat around the bush”, etc.)

Since he’s a Muslim who follows his faith devoutly, Lupe doesn’t do drugs (“horse” is slang for powdered heroin), but he does toot his own horn (promoting himself and his records). A unicorn is a white horse with a horn. Horses often “snort” when they neigh.

Note that the reference to tooting his own horn foreshadows the tuba reference in the next verse.

Mario Bros reference:

Possibly a double entendre as a reference to marijuana. High quality weed is often referred to as “fire”, with the flower of the plant being that which one smokes.