No one shall be subjected to arbitrary arrest, detention or exile.
Everyone is entitled in full equality to a fair and public hearing by an independent and impartial tribunal, in the determination of his rights and obligations and of any criminal charge against him.
But what does this mean for me?
Not all arrest and detention is arbitrary. Say you're hanging out with a bunch of your friends at Denny's, innocently scarfing down your Moons Over My Hammy and talking about how great Hayden Christensen looks with his shirt off (or, if you prefer, Angelina Jolie in a vinyl bustier) when the police bust in and arrest the lot of you for robbing a convenience store, and you have no freaking idea what's going on. When they take you back for questioning, they discover that while your friends were, in fact, robbing that convenience store, you were delivering the keynote address at a symposium on theoretical partical physics and three hundred people can attest to your whereabouts. At this point, the police have two choices: they can let you go, or they can suspect that you might have had a hand in planning the robbery and hold onto you, interrogating you throughout the night, not letting you sleep, playing loud music constantly, and handcuffing you naked in the fetal position in a freezing room in a puddle of your own feces until you crack and tell them something, anything, whether it's true or not.
Wait, no, the police can't do that last part.
Of course, international terrorism is waaaaaay more serious than knocking over a 7-11, and of course more intense interrogation methods are warranted in that case, and I'm sure that none of the detainees had an airtight alibi for whatever they're being accused of. But as for you, stuck in the interrogation room for five hours without so much as a potty break, since the police don't seem to believe that you had no involvement in the robbery, you'll probably be pleased to know that you're entitled to a fair and public hearing by an independent and impartial tribunal - no imprisonment without cause, no pretend trial with your arresting officer as judge, and no secret tribunal - if your rights aren't upheld during the trial or if you're sporting size 11 waffle-tread bruises, the entire country gets to know about it.
Just answer the question already.
It means that if they arrest you, they have to have a good reason for it, and that reason has to hold up in a fair and public hearing.
Part I: The Preamble; Part II: Articles 1 and 2; Part III: Articles 3 and 4; Part IV: Articles 5 and 6; Part V: Articles 7 and 8