To add to the mix, consider this:
“In the ancient world, particularly in the ancient near-east (Israel, Mesopotamia, Egypt, Persia) names were thought to be extremely powerful and to act, in some ways, as a separate manifestation of a person or deity.[4] This viewpoint is responsible both for the reluctance to use the proper name of God in Hebrew writing or speech, as well as the common understanding in ancient magic that magical rituals had to be carried out “in [someone’s] name”. By invoking a god or spirit by name, one was thought to be able to summon that spirit’s power for some kind of miracle or magic (see Luke 9:49, in which the disciples claim to have seen a man driving out demons using the name of Jesus.) This understanding passed into later religious tradition, for example the stipulation in Catholic exorcism that the demon cannot be expelled until the exorcist has forced it to give up its name, at which point the name may be used in a stern command which will drive the demon away.”
And:
“The Babylonian Talmud maintains that names exert a mystical influence over their bearers, and a change of name is one of four actions that can avert an evil heavenly decree, that would lead to punishment after one’s death. Rabbinical commentators differ as to whether the name’s influence is metaphysical, connecting a person to their soul, or bio-socio-psychological, where the connection affects his personality, appearance and social capacities. The Talmud also states that all those who descend to Gehenna will rise in the time of Messiah. However, there are three exceptions, one of which is he who calls another by a derisive nickname. A myth is a message that is passed on from generation to generation.”
Souce - Lazypedia. Er, I mean, Wikipedia.