I'm not generally one to bore with the facts. A simple "Google" search on the origins of Halloween can bring you this information, but I thought I'd condense it a bit for the sake of the lazy reader like me.
The Origin
You can trace the origins of Halloween back a number of different ways, but most will lead you to a Celtic Festival called "Samhain" which celebrated the changing of seasons and their "new year" on November 1st. The Celts believed that on the eve of their "new year" the boundary between the dead and the living became blurred. On that eve of the "new year" (October 31) they believed that the ghosts of the dead returned to earth.
On that eve, the Celtic priests (also known as Druids) built huge bonfires and offered crops and animals as sacrifices to Celtic deities. During the "celebration", the participants dressed up in costumes and tried to tell each other's fortunes. When the Romans conquered the Celtic territory, they combined their pagan festivals into one.
Traditions like bobbing for apples find their origin in the worshipping of the Roman goddess of fruit and trees called "Pomona". The symbol of Pomona is the apple (we French speakers know the word for applie is "pomme"). Even the tradition of the "jack-o-lantern" is historically based on a mythological character.
Years passed and with the influence of Catholicism, celebrations evolved into what we now call "All Saints Day" on November 1 or loosely translated from Middle English, "All-hallows". The day before "All Saints Day" was known as "All-hallows Eve" or what we now call "Halloween".
Dressing in Costume
Celebrations were marked by bonfires, parades, and people dressing up in costumes as saints, angels, and devils.
The History Channel reports some interesting background on Halloween:
"The tradition of dressing in costume for Halloween has both European and Celtic roots. Hundreds of years ago, winter was an uncertain and frightening time. Food supplies often ran low and, for the many people afraid of the dark, the short days of winter were full of constant worry. On Halloween, when it was believed that ghosts came back to the earthly world, people thought that they would encounter ghosts if they left their homes. To avoid being recognized by these ghosts, people would wear masks when they left their homes after dark so that the ghosts would mistake them for fellow spirits. On Halloween, to keep ghosts away from their houses, people would place bowls of food outside their homes to appease the ghosts and prevent them from attempting to enter."
Speaking as a Christian, we are not to make idols of the dead. We honor the dead, but we don't worship the dead. There is only one who gets the "worship" in this deal and it's God. The dead are dead. Let their bodies be in the grave and their souls rest in heaven or hell.
The Origin of Trick-or-Treating
It's been suspected that the act of going from door to door to get candy traces back to the All Saint's day parades when during the festivities, the poor would go around to peoples' houses begging for food. Families who answered the door would give them pastries called "Soul cakes" in return for their promise that they'd pray for family's dead relatives. This practice was eventually given over to children and intended to replace the tradition of leaving out food for "roaming spirits".
Today
Jump to the present. There isn't a lot that has changed from the past. During the 19th century, there was a move to center Halloween on family and community, but the roots and traditions are still visible and prevailing.
It is widely known that Halloween also serves as a time for those involved in the occult to commemorate their own sacred rituals. Covens gather and the worshipping of spirits commences. We often turn our shoulder, but the Wiccans, witchcraft, and demonism are very real and very prevalent in our society. There are many things I'm willing to tolerate and entertain, the occult is not one of them.
Many would argue that the holiday is all in fun and while I agree there are aspects of this celebration that seem harmless, the undertones are not something with which I personally desire to associate myself or my future children. Aside from trick-or-treating, the fruit of this holiday is arguably not heavily weighted towards "community". The abundance of haunted houses, witches, devil, and ghost costumes, séances, scary stories, and the general presence of "death" is not edifying in the least.
I believe people should act according to their convictions. If you choose to celebrate this day by putting your own moral "twist" on it, so be it. But I also believe we're accountable for what we know. Many black Christians know the negative origin and roots of Kwanzaa but choose to celebrate the holiday anyway. I am not one of those people. For those who profess to be believers in Jesus Christ, the connotations of Halloween are not good. The foundation for Halloween is steeped in paganism.
With Americans spending an average of $6.9 billion (not million) to commemorate Halloween, that makes it the second largest commercial holiday of the year. When people ask me what I'm going as for Halloween, I say, "I'm dressing up as the wacky Christian girl who believes the holiday is pagan."
Hallelujah, sister!
Finally, someone who agrees with me that this is one "holiday" that shouldn't be recognized.
I have always thought it a bit unseemly, too, for kids to beg for candy.