There are a number of good articles out there for understanding All Hallow’s Eve (Halloween), Reformation Day, and All Saint’s Day. Here are one, two, three excellent ones that will make you wrestle with the issues.
All Saint’s Day is Nov. 1st, a day dedicated to remembering all the Christian martyrs. It’s appropriate to give thanks for the seed that went into the ground and grew us up. Too often Protestants treat All Saint’s like another gaudy Roman Catholic addition to the calendar. Ironically, it’s an antidote to the Rococofied celebrations for a different saint taking place every five minutes in the city of seven hills. Martin Luther posted his 95 Theses on Halloween, the eve of All Saint’s precisely because it was the time to celebrate and continue the church’s victory over Satan, sin and death. None of his Theses rejected All Saint’s, just the covetous superstition of indulgences that marked it at that time.
Any church or group of churches recovering a sense of history and true catholicity has to be discerning. What should we recover, leave alone, repent of, or consider for a while before we employ? Bible study and more Bible study is called for. If you like All Saint’s Day (and I think you should), you should reject (with equal joy!) the following day, November 2, All Soul’s Day. In 1048, Saint Odilo, the Abbot of Cluny, had a vision (derision?) of the saints suffering in purgatory. His vision directed him to perform masses on behalf of said dead, thus freeing them from purgatory. By the end of the 13th century, All Soul’s was a staple in the Western church until Luther lit the match on Oct. 31, 1517 that blew up the idolatry of the church.