Wherefore come out from among them, and be ye separate, saith the Lord, and touch not the unclean thing; and I will receive you... 2 Corinthians 6:17
"AdventHealth in Tampa is ready for Halloween this October 31, 
2020. They recently had a contest to see who can design the best jack-o-lantern, which are the famous pumpkin faces that are typically made for Halloween. As Christians, we should be concerned about the observance of Halloween.
“I saw that our holidays should not be spent in patterning after the world, yet they should not be passed by unnoticed, for this will bring dissatisfaction to our children. On these days when there is danger that our children will be exposed to evil influences, and become corrupted by the pleasures and excitement of the world, let the parents study to get up something to take the place of more dangerous amusements. Give your children to understand that you have their good and happiness in view” (Testimonies, vol. 1, p. 514).
I doubt that Mrs. White was even considering Halloween when she wrote the above statement. The word “Halloween” does not even appear in any of her writings. But she advises us not to act like the world and I’m sure this involves dressing our kids in hideous 
costumes. This cannot be representative of our Savior.
Seventh-day Adventists should instead commemorate Reformation Day every October 31. It was on October 31, 1517 that Martin Luther nailed his Ninety-five Theses on the Wittenberg Church door, which is considered by Protestants as the start of the Reformation. Let’s commemorate the spiritual liberation that followed Reformation Day.
Let us commemorate the spiritual heritage of Reformation Day, instead of the pagan superstitions of Halloween:
“It was the work of the Reformation to restore to men the Word of God” (Great Controversy, p. 388)." AdventMessenger