Is this even legal ????

Somehow I doubt it.
You can't have a Nativity Scene in public at Christmas because anything Christian might offend some extremely weak minded frail liberal and here is a sign over a public highway (in your face) asking you to pray, but you may say any religion can pray, true but anyone who sees this is not thinking it refers to Allah. If you have any doubts do a Google search for any Muslim groups holding a prayer meeting.


Now I know this is illegal, high school girls wearing shirts to 'Pray 4 Boston'

I would think if the ACLU finds out this was at school they would fight to have them kicked out of school.
 How dare they try and drag God back into this after the government has fought hard to kick him out.