Okay, I know what i'm about to say isn't that bad, but it's about social things that I don't understand, so here goes…

I have lots of friends, some I talk to everyday, some I talk to every couple of days… But there is this one friend, my best friend, he is constantly depressed, and I don't know why, he has cut himself before but not recently which is good, he still punches walls really hard and gets to the point were he nearly breaks his hands, he also constantly asks people to hurt him. I need some advice on that, I don't know how to help him, every time I try he refuses and doesn't talk to me for a day or two.

I know it is not really my problem, but I feel as if I have to help him, but I don't know how.
Can I have some advice please guys?

I guess since he won't tell you why he's depressed, you can't really do anything specific to help, but just doing stuff that would make anyone happy (basically just anything fun) would probably help take his mind off it.

Self-harm (which can take the form of things like punching walls, though cutting is the most well-known) and depression are pretty serious issues and it sounds like he may need help from a professional. It's good to care about these things, especially because people with depression can feel very isolated, so let him know that you've noticed and you care. Some depression doesn't have a cause, it's because the person's brain isn't functioning properly. Help him get an appointment with a psychologist or therapist, try to be very patient and polite when you suggest this.

Since you don't know what his problems is, try staying neutral with him. He obviously doesn't care about himself but if you really do care be there to talk with him and keep his mind off things, maybe offer him help but let him open up to you. He's your best friend he'll eventually spill it out what he's feeling that's bothering him. Don't be overly surprised about things or feel bad too much because then they get this feeling of pity but you're just listening to them and letting them get it out their feelings without them hurting themselves you rather they talk and express it. Try to make that clear you're a friend that you care about and you won't forget him to remember your friendship. He might be going through a lot but he can't forget the others he's leaving behind that cares and want to help. It is selfish for a person to do that.

Thanks guys

I also want to let you know it is important to tell us things like that so don't worry. ^_^