Here's the original link where I found this article, and scroll down to where it says "Halloween":
The October 31st holiday that we today know as Halloween has strong roots in paganism and is closely connected with worship of the Enemy of this world, Satan. It is a holiday that generally glorifies the dark things of this world, rather than the light of Jesus Christ, The Truth.
Have you noticed how costumes and masks are getting generally more bloody, gory, and depraved each year? Unfortunately, the gruesome and grotesque and the occult are increasingly glorified in American society, not only on Halloween, but throughout the year in frequent horror movies and television programs
My family does not celebrate it or participate in it. We do not believe that our children are “missing out,” and neither do they. Other days are used for costumes and parties. Happily, all of our children have accepted Jesus Christ as their personal Savior. We have found that Halloween provides an excellent time to remind our children that, as Christians, we are different, and not of this world (Heb. 11:13-16; 1 Pet. 2:11).
What about church “Harvest Festivals” held on October 31? Although we understand the rational and good intentions behind them, we don’t think they are the best approach. Our family tends to agree with the author of an article called “Are ‘Harvest Parties’ for Christians?” (written by a self-avowed former witch and now active Christian). Harvest parties on October 31 tend to assume that “our children need something to take the place of Halloween, since they won’t be participating in the secular and pagan celebrations. It suggests our kids are missing out on something. And indeed they are, if we allow them to spend Halloween in celebration.” There are better things to do on Halloween than partying.
Also, we need to teach our children that “the fight isn’t against occultists, non-Christians, Christians who feel differently than we about Halloween, or institutions that promote Halloween, but” “against principalities, against powers, against the rulers of the darkness of this age, against spiritual hosts of wickedness in the heavenly places” (Ephesians 6:12, NKJV).
Here are some relevant scriptures to back up this article:
1 Thessalonians 5: 21-22