Language geek help needed

[seticat]

I just got a t-shirt prezzie in the mail from friends, but #1: I don't speak Latin and #2: I *know* these folks - I want to know what it says before I wear it out and around in a good, church fearing, college town [also a good church college town where there's bound to be someone who could actually read it].

Can someone tell me what "Ea cui oboedi = endum est" roughly means? Google and Babel Fish aren't much help with this so far.