21st Sunday after Pentecost 2022. Halloween?

Friends, this is the 21st Sunday after Pentecost in the year of our Lord 2022. The following three days we have interesting things happening. Tomorrow is what is called in the west; Halloween which is in fact the Christian "All Hallows Eve". What does this mean and how can it be Christian? The next day will be All Saints Day and then the following day will be All Souls Day. What does this mean in the Western Church and also does the Eastern Church recognize these days as holy. Join us. Blessings, +William