Considering the source, you are completely free to take my thoughts on Halloween with a grain of salt. I'd put Halloween symbols and characters--not exactly--but on a similar plane as Christmas elves, magic, evergreen boughs, trees, and yule logs, stockings, 'exchange' of gifts, etc....which are all historically connected to non-Christian and pre-Christian myths, traditions, and human anxieties.
Although I don't see Halloween as a strict dichotomy of the powers of darkness against the Light, I agree that many aspects of Halloween seem to flirt with darkness. To me, however, with its costumes and traditions, Halloween mostly dominates, diminishes, satirizes, and thumbs a nose at the darkness, especially when you open the door and see a mini-ghoul standing next to a fuzzy little panda bear both saying "Twick-o-tweat."
It is a self-indulgent and consumerist tradition, yes. At the same time, as I walked with my boys trick-or-treating, or stood at our door with them, there were opportunities for teaching and showing "how we conduct ourselves" as decent people, via greetings, compliments, sharing, and being fair. I got to meet some of the neighbors, and neighbors' kids that I've only seen in passing.
I'm not going to suggest that there is any specific Christian value, moral or otherwise, to attach to the way we do Halloween ...except perhaps to suggest that the dark elements represented within Halloween (i.e. witches, pitch-forked demons, monsters, etc.) have no authority or power over the Christian, even when I am in the midst of them. Against the faith established by God, they are plastic masks and hollow pumpkins. In fact, underneath the costumes are still human children or adults. Their costumes don't dictate who they are, how they act, or who they will become. We Christians, strengthened by the Spirit, have authority over how we conduct ourselves within--or apart--from all the elements of Halloween.
We hold a Halloween party at our church with a potluck dinner, carnival games with candy prizes, finishing with a "trunk-or-treat" in the parking lot. Kids go from decorated car trunk to trunk where they receive still more candy. I know that for some of our current members, as superficial an introduction as that Halloween party may seem, it was one of their first cautious steps into a deeper relationship with a church family, and then with Christ.
I can see how the slippery slope of ambiguity might be ugly or distasteful for some. I like fantasy novels, including magic, elves, dwarfs, demons, angels, etc. I especially enjoy some of the real spiritual warfare that some fantasy authors like to explore with those fictitious characters. Some can't stand it, and can't get past the fiction and general weirdness to hear any "truths" the story might want to describe. It's not for them.
Likewise, many Halloween costumes are ridiculous representations of evil, the occult, or violence; for many people, making light of this isn't funny or entertaining. For them, or for those who like it too much, abstaining from Halloween (or any of the more historically pagan or self-indulgent observations) may be a fine choice. That's especially true if the abstinence is used as a spiritual discipline or internal retreat, following Jesus' guidance re: quiet prayer and fasting (Matthew 6).
Perhaps a person of conscience could use Paul's various suggestions about what to do in the presence of meat sacrificed to idols (1 Corinthians 10). While he acknowledged that the meat itself is not tainted, he warned them to avoid knowingly participating or supporting idol-worship. It shouldn't be cause for rudeness, nor should our freedoms be carelessly flaunted.
However, I don't feel that shared Halloween candy is what Paul had in mind. I respect some of our neighbors who, for religious reasons, didn't carve pumpkins, decorate, or send their kids out to trick-or-treat, but still kindly opened their own door to greet and give treats to the kids who knocked. That's a generous thing to do. Or those who chose to turn off their lights and go somewhere else for the evening.
Now, if Halloween (and/or participation in it) is inherently evil, then none of these arguments--that it builds relationships or thumbs our collective nose at darkness--bear any weight. If it really is engaging in pagan worship, it would be wrong for a church to hold a costume party or trunk-or-treat event. We wouldn't use prostitution as a means to build relationships, spread the word, or to "thumb our nose" at anything. So, my obvious bias is that Halloween and its masks are not evil in themselves. I grew up with it, still observe it, and I preach the gospel. I don't worship Satan; never did, not even if I once wore a vampire costume.
More than battling fictitious and obvious representations of old myths and superstitions, I think God is still more interested in spending our time and energy on the things that seem to take precedence in scripture like love, mercy and justice: are the hungry ones being fed, the widows and orphans being cared for? Are the sinful, lost, lonely, and afraid ones hearing the gospel of grace, and finding companionship and assurance?
For me, condemnation of all Halloween activities sounds a bit like ritual-purity and the ascetic rigor that re-imposes Pharisaism and its worship of separation and code. Jesus stood against that message when he preached about Sabbath and ritual purity versus compassion. Granted, there is little in Halloween to do with grace or compassion, and yet both the central belief that we are "saved by grace through faith in Jesus Christ" and also the central commands for love and loving action toward God and our neighbor both get hidden, lost, and forgotten in wave after wave of modern mid-rashes on the thou shalt not's. I wonder if there isn't a way to warn against specific vices of Halloween (i.e. greed, self-indulgence, and consumerism) to help Christians navigate the day, without making a hard-line polemic against it.
To sum up, Halloween might be one of those things that we are "free" to do as Christians... but is it beneficial for the weak in faith or the non-believer? Again, it may depend on who we are with, how we conduct ourselves within it, and how we choose to separate ourselves from it.
