Christian: Jesus is a man of peace!
Jesus speaks (Matthew 10:34)
Jesus: I come not to bring peace but a sword.
Christian: D'oh!
Jesus makes peace between God and man. When, as a new convert to Christianity, that new convert tells his family and friends, a "sword" comes between him and his family. If you are baptized in Mooslim countries, you are summarily executed, and, usually by your own family. That is what is meant by His bringing a sword. He does go on to explain it, if taken in context. It does make Jesus sound contradictory and kind of stupid when quoted in the short version you prefer, though. Here is the complete quote from Matt.
10:32 Whosoever therefore shall confess me before men, him will I confess also before my Father which is in heaven.
10:33 But whosoever shall deny me before men, him will I also deny before my Father which is in heaven.
10:34 Think not that I am come to send peace on earth: I came not to send peace, but a sword.
10:35 For I am come to set a man at variance against his father, and the daughter against her mother, and the daughter in law against her mother in law.
10:36 And a man's foes shall be they of his own household.
10:37 He that loveth father or mother more than me is not worthy of me: and he that loveth son or daughter more than me is not worthy of me.
10:38 And he that taketh not his cross, and followeth after me, is not worthy of me.
10:39 He that findeth his life shall lose it: and he that loseth his life for my sake shall find it.
10:40 He that receiveth you receiveth me, and he that receiveth me receiveth him that sent me.
So, it is peace between man and God that Jesus brings. Full atonement. Complete payment for the sin debt a man owes before God. And now, are you willing to confess that you are quoting Jesus out of context, or are you reverse-SPAGing all who might read your tag?