I don’t know. And what’s more, I don’t care. First let me quickly deal with I don’t know, before moving on to the far more significant I don’t care.
The Bible does not say, “Thou shalt not celebrate Halloween.” It certainly doesn’t say, “Though shalt not dress thy little girl as a princess, walk with her through the neighborhood and collect tasty treats.” It does, however, far more than we Christians, take very seriously the supernatural realm. When God established Israel He commanded that witches there be put to death. The same for necromancers. He understood that these are not games to play with, but deadly serious matters. To the extent that celebrating Halloween means playing fast and loose with such things, I would strongly discourage it. That said, even if we confess that this was its origins, it still doesn’t mean dress up and candy are sins. As long as we stay clear of the macabre, I’d argue it’s a meat offered to idols issue. If your conscience is troubled, steer clear. If not, I won’t fuss at you about it.
That said, this is a question I’m not in the least concerned to answer. In my family this is a non-issue. We do not celebrate Halloween, but not because we’re certain doing so is a sin. We don’t celebrate Halloween for this simple reason- because we’re far too busy and far too giddy celebrating something far more significant. No, it’s not a harvest festival. (Indeed I would argue that the sanitized Christian substitute version of Halloween, wherein we call it something else, and dress up as Bible heroes may be the worst possible choice. We copy the ways of the world, badly. It’s the October 31st version of what goes on every Lord’s Day in happy clappy churches, a third rate copy of the world’s inanities.)
We don’t celebrate Halloween because we are too focused on celebrating the Reformation. October 31st marks the anniversary of Luther nailing his 95 these on the church door in Wittenberg. We rejoice that God in His grace emboldened Martin Luther to stand on the promises of God. We give thanks to God for recovering for His people the clarity and simplicity of how we might have peace with Him through the finished work of Jesus Christ. We celebrate the recovery of the Bible as our alone final standard of faith and practice, the ending of the Babylonian captivity of the church. This is not some bland Christian substitute for Halloween. This is the real deal.
Saint Peter Presbyterian Church holds a wonderful three day celebration starting with a bonfire and s’mores party, then a day-long festival, complete with crafts, booths, food, games, contests, the reading of the 95 theses, the retelling of the story of Martin Luther, music and dancing and then a joint worship service on Sunday. The puny and pathetic parties of the world won’t hold a candle to ours. Halloween is a dead issue. The Reformation, that’s life.