I have seen these guys on the street in philadelphia for many years. I usually ignore them, but I found myself near city hall today and decided to sit and eat a cheesesteak while I listened to their public sermon.
Because I am mobile, I will keep this very brief (and I will write more later). Their basic message seems to be that many of the non-white people of the world (all in the western hemisphere) are the 12 lost tribes of Israel, and that they are the people of (the biblical) God.
They also argue that Jesus was black, which has gained some traction in segments of culture in recent years (for me, this idea first appeared in the music of KRS-ONE). On top of that, they have a generally dis-favorable view of white people. At one point a few years ago, one of them referred to me as a white devil (this may remind you of the Nation of Islam).
Their sign lists two verses from the Old Testament:
I don’t know them off-hand, but I will look them up later for further comment. I will listen for a little while longer.
(BTW, when I tried to take the picture, one of them tried to block me with his clipboard. I had to explain to him the concept of public space and the first ammendment, of which they are now protected under.)