According to Wikipedia,
Halloween is typically linked to the celtic festival of Samhain which is derived from Old Irish and means “summer’s end”. The festival of Samhain celebrates the end of the “lighter half” of the year and the beginning of the “darker half”, and is sometimes regarded as the “Celtic New Year.”
The celebration has some elements of a festival of the dead. The ancient Celts believed that the border between this world and the Otherworld became thin on Samhain, allowing spirits (both harmless and harmful) to pass through. The family’s ancestors were honored and invited home while harmful spirits were warded off. It is believed that the need to ward off harmful spirits led to the wearing of costumes and masks. Their purpose was to disguise oneself as a harmful spirit and thus avoid harm. In Scotland the spirits were impersonated by young men dressed in white with masked, veiled or blackened faces. Samhain was also a time to take stock of food supplies and slaughter livestock for winter stores. Bonfires played a large part in the festivities. All other fires were doused and each home lit their hearth from the bonfire. The bones of slaughtered livestock were cast into its flames. Sometimes two bonfires would be built side-by-side, and people and their livestock would walk between them as a cleansing ritual.
Another common practice was, divination which often involved the use of food and drink. The name ‘Halloween’ and many of its present-day traditions derive from the Old English era. http://en.wikipedia.org/wiki/Halloween
The Bible doesn’t speak directly about Halloween, but some biblical principles apply. One overriding principle is clear — all pagan practices should be avoided. Witchcraft, occult practices, sorcery, etc. are strictly forbidden in the Bible (Exodus 22:18; Acts 8:9-24; Acts 16, 19). It is obvious that a small child dressing up as a character to go trick or treating isn’t involving themselves directly with witchcraft but what are the boundaries that a responsible Christian parent should set up?
Parents, the decision is up to you, but do not proceed in your decision from a place of ignorance.
If you decide Halloween is something fun for your children, it is probably most important that they are kept far away from the evil aspects of Halloween. When believers participate in anything (even Halloween), their attitudes, dress, and behavior should glorify Christ.
Every year at Crossroads Church of Denver we offer a special alternative celebration for parents who are interested in allowing their children to dress up and go trick or treating in a controlled environment. This year the event we are offering is a Trunk or Treat Celebration. The event is held in our parking lot and we encourage participants to dress up and decorate their open car trunks as a site for handing out candy to the kids. The children go from car to car collecting their treats and a great time is had by all. The parking lot is well lit, safe and secure and participants are monitored (nothing evil or too scary allowed)!