For all you unfamiliar with sales, this is what's referred to as, "the close". I highly doubt Zuckerberg thought about the biblical overtones. It is, an easy way to close a prospect, and a great way to convince somebody to join Facebook.

It would be the same as a highly recruited athlete in high school. You take the tour of the college campus, then they lead you to the stadium and say, "Imagine Nick, 30,000 fans screaming your name every Saturday afternoon."

It's just a sales pitch, nothing more, nothing less.