The ancient Celtic celebration of Samhain occurred on November 1. It was a kind of New Years holiday from which All Saints' Day and All Hallows Eve derive. Along with the days immediately before and after, Samhain was special because the Celts believed that the boundary between this world and the spirit world relaxed or lifted. This allowed spirits to cross between the worlds more easily. Superstitious people mollified the spirits by leaving out food and treats so that the spirits would not curse them. Some practiced various forms of divination to contact departed loved ones. Druids thought this to be the best time to seek guidance from the dead. Bards sought otherworldly inspiration for their poetry and song. The Celts considered Samhain to take place in no-time, that is, neither in the old year nor the new. Normal laws, order, strictures, and customs were held in abeyance for these three days of merriment. People did whatever they pleased. The fool held court as the wise man. The baseborn acted as the noble. The servant became the master. Women dressed as men, and vice versa. Farmers turned out their cattle, pigs, and sheep from their pens and pastures, allowing them to roam free. Some entered houses through windows rather than doors. No work was done because it was a time of total abandon of revelry, feasting, drinking, taking dares, disguising oneself, and pretending to be something one was not. Those three strange days were chaos time.

Samhain was the Celtic festival held on the three days around November 1 that combined a New Year's celebration with a harvest festival. The Celts viewed this period as a unique transition between the old year and the new during which the boundary between the physical and spiritual worlds relaxed, permitting spirits to cross over more easily. They particularly feared the spirits of those who had died in the preceding year, believing these spirits sought to return to the mortal realm, and therefore sought to appease them by setting out food and treats so the spirits would pass by without harm. Failure to appease the spirits, they held, would result in tricks or curses, prompting whole villages to unite in efforts to drive evil spirits away and secure a favorable coming year. Some participants also conducted séances and other forms of divination through incantation, potion, or trance in order to contact dead ancestors and obtain guidance. The Celts regarded the three days of Samhain as no time at all, a suspension of normal order in which laws went unenforced, social roles reversed, people disguised themselves and acted out alternate personas, and the community engaged in revelry, drinking, eating, dares, and lawbreaking. Halloween in English-speaking countries derives primarily from this festival, and its present customs of trick-or-treating, divination, and vandalism represent a reversion to the original Celtic practices. These elements illustrate why the holiday constitutes an idolatrous mixture of paganism and spiritism that God forbids, because it honors unseen spirits rather than the true God and leads participants away from covenant faithfulness.

Sunset on October 31 marks the beginning of All Hallow's Even, better known as Halloween, which originated in the pagan Celtic harvest festival Samhain. This festival incorporated spiritism and superstitious rituals that the Roman Catholic Church later co-opted and merged with its own observance of All Saints' Day. The celebration centers on the dead and ultimately glorifies Satan the Devil, whom Scripture identifies as the ruler of this world and the deceiver of humanity. Through such traditions, the world promotes a false understanding of death and an immortal soul drawn from pagan sources, in direct opposition to the biblical revelation of God's purpose. That purpose centers on forming a divine Family, with the Father and the Son already in heaven and those begotten by faith and the Spirit becoming children of God. Evil stands as the direct antithesis of the eternal life found in knowing the Father and the Son, and Halloween's rituals of trickery, sorcery, and spiritism align instead with the malignant ways of the evil one. Christians therefore face the same fundamental choice presented to Adam between life and evil, a choice that requires rejecting every form of evil and overcoming it through the good that flows from relationship with God.