I love the Malcom X and Muhammad Ali quotes. Here's some more:

'Be peaceful, be courteous, obey the law, respect everyone; but if someone puts his hand on you, send him to the cemetery. ' - Malcolm X

'The future belongs to those who prepare for it today.' - Malcolm X

'I believe in the religion of Islam. I believe in Allah and peace.' - Muhammad Ali (this might be more effective if you have a large pic of him as well)

'I run on the road, long before I dance under the lights.' - Muhammad Ali (maybe could use it as a reference to working in this life to gain Paradise?)

'We have one life; it soon will be past; what we do for God is all that will last.' - Muhammad Ali (BRILLIANT!)

'If they can make penicillin out of mouldy bread, they can sure make something out of you.' - Muhammad Ali (I don't know how relevant this is; it just made me laugh)