The word 'Halloween' comes from 'All Hallowed's Eve', I think it is, the evening before All Saints' Day. But it falls on the night of an old Druid celebration. The Druid religion was a pagan religion that had great influence before Christianity entered Britain. A number of the customs, came from pagan customs, like carving a face on vegetables, which was supposed to scare away spirits. These pagans believed that ghosts roamed around on those nights. So going around begging for food on that night, the obsession with ghosts and spirit beings, etc., on that night have to do with the pagan holiday.
I don't celebrate Halloween. I don't want to dress my kids up like ghosts or whatever on that day. I wish our forbearers had done a better job at stamping out pagan practices and references from our culture, like the names of months and days of the week and holidays like this.
In the Old Testament, we can see that the appeal of pagan holidays and customs influenced Israel. Apparently, some Israelites were weeping for Tamuz. Israel came under judgment when some Midianites and Moabite women invited them over for barbecue and sex. This must have had a great appeal. It could have happened at some holiday, some Baal of Peor day. We don't know. But the meat offered to Baal probably tasted good. And I'm sure a lot of those men enjoyed the fornication. But lots of Israelites died over it.
So how should we respond to Halloween? There are those who say it doesn't matter, since a lot of people don't associate the things they do with the old pagan practices and religious observances they grew out of. Then there is the approach that we can use it for outreach, don't encourage dressing up like monsters, but give out candy at church and put on a play about Jesus while the kids come in in their costumes, or whatever. We could also satisfy the children's desire to dress up by celebrating Reformation Day (Oct. 31, 1517 when Luther nailed the 95 theses on the church door at Whittenburg) or all saints day. So all the girls get to dress up like one of a dozen or so Biblical and historical figures. Boys can put on fake tent pegs that look like they go through their skulls and be Sisera, or wear a tunic and carry a stuffed lion and pretend to be Samson. Or they could dress like a monk or knight (Sir George) and be Martin Luther. This would be more fun for the boys and most kids would wear bathrobes and towels.
We could also just not dress up as a kind of protest, almost, or just ignore the holiday. Let the kids whine about not getting candy if they must. We could dress up for Purim like the Jews do, and wear costumes to a puppet show about Esther and Haman.
I don't know the perfect solution. Conscience has a lot to do it. We don't celebrate Halloween. I'm not against outreach. I've taken my kids to church events where they give out candy.