From Lifeway Research:
By Becky Kiser
Traditionally, Thanksgiving (or “day of thanksgiving”) was set up to celebrate a harvest of God’s favor, protection, and blessing.
George Washington first declared it a national holiday in November 1789, more than one hundred years from the first documented one in Plymouth in 1621 (though rumor has it that some colonies boasted a day of thanks before even that date!).
As very few of us still celebrate an actual harvest, it is now a cultural celebration of giving thanks for all we have received this past year.
It’s a season to count our blessings and celebrate with gratitude with others. More Here