In response to: http://www.fivedoves.com/letters/june2011/alanc68.htm
In your post, you said that the Bible declares that Pentecost is ALWAYS on a Sunday.
In Bible times, they used the expression “the day after the Sabbath” or “the morrow after the Sabbath” or “the first day of the week”, which are equivalent.
All these expressions mean the same thing, which is “the day after the Sabbath”. However, this day (the day after the Sabbath) is only equivalent to Sunday (in the Gregorian calendar that we use nowadays) if you believe that “Sabbaths” are the same thing as “Saturdays”.
Is this assumption true? No. The Sabbaths followed a different logic, they were regulated by the phases of the moon.
See explanation here: