How to block friends from messaging you on Facebook?

[IJSI]

So I have approved a Facebook friend request from a guy at work, no big deal right. Turns out he is a little obsessed with me, and its creepy. I don't want to make it extremely awkward for weird, but I do want him to stop creeping me out. So I have decided not to remove him as a friend, but restrict what he can, and cannot see( again so I limit the awkwardness).Therefore I have restricted him and taken all measures I can to make sure he cannot, well, creep me. The last thing I have left to do is block him from messaging me. I have intensively searched how, but every way I have found is outdated. I would SOOOOO appreciate if someone could give me a procedure or something on how to do so. I don't need it that much in depth but, just enough so I can follow along. If possible a list of ways to restrict would be a nice bonus(in case I missed anyways to do so) but I certainty don't expect anything to in depth. Please help, it would be greatly appreciated. Thanks to those who give real answers and solutions. To those who just say block him, unfriend him, e.t.c well u sorta suck (no offense, actually yah offense u r stupid), sorry to get a little rude but I want serious help. Again please help, and thanks to those who really do.
lovemusica- Thx for doing what I directly said I didn't want someone to do.... On the bright side it was at least very in depth, so if I did want to block him I would know how.

Jorge- Thx for the tip il try it. Also it would make sense for Facebook to do that for well, situations like this, and in general privacy issues.

Daniel- I don't know what is up with you overuse of capitals but whatever. Your tip was very helpful in the sense it saved me from spending hours looking for a lost cause. Thx I appreciate it.

I am still open for any other suggestions, tips, tricks, advice, e.t.c, although I doubt I will get anymore.

[lovemusica]

You can just block him by:
1:go on Facebook
2: click on account settings
3:click on the 'blocking' button
4: type in his name(make sure no mistakes)
5: look for his picture,or the one you know is him
6: andddd that's it. He can send you messages,post on your timeline, or anything. And he won't ever know. And if he finds out he can't do anything about it because he can't message you not anything. Good luck Byee

[Jorge]

Theres no way to stop him from messaging you, but you can get his messages moved to another inbox "folder", if what I'm reading from the official Facebook page is correct. See source for more details.
Wouldnt really make sense for Facebook, a social network, be able to allow you to block people from messaging you.

[Daniel]

There is No Way to Block People From Messaging you They Use to Have a Feature Where you Could Block Messages All Togather But They Dont Have That Anymore