"When Obama brushed dirt off his shoulder during the 2008 presidential campaign in an obvious reference to Jay’s song ('Dirt Off Your Shoulder'), Jay was amazed. 'I was like, This is not happening in the world... growing up, if you had ever told a black person from the hood you can be president, they’d be like, I could never. If you had told me that as a kid, I’d be like, Are you out of your mind? How?'
When I asked him if the only way black kids thought they could get out of the projects was by being a rapper or a basketball player, Jay said, 'Exactly. That’s the only thing we saw.'
...But he added, 'The middle class has been eliminated; it’s so hard to make a living now. There’s a bigger gap between the haves and have-nots, and that’s what creates the problem. It’s going to bring some sort of anger, it’s going to boil over, and there’s going to be a conflict. Everyone has to participate in this American Dream, and if everyone’s not participating, then there’s a problem.'
'It’s not cool—the trajectory that this is going. We have to figure out how to include everyone.'"
-- The whole Jay-Z profile in the November 2013 issue of Vanity Fair is top-notch, and fortunately it's all available to read online. This is just one good bit.
And you can see the video of President Obama dusting his shoulders off back in 2008 here.