It was Lincoln who declared the first national holiday that we know and celebrate every November.
It was 1863 and we were still in the throes of the Civil War. Tens of thousands of soldiers had been slaughtered on the fields of war, including the recent battles at Gettysburg and Vicksburg. Nonetheless (or maybe precisely because of this), Lincoln called the nation to a time of public Thanksgiving. Citizens were asked to offer their gratitude for the many blessings, even as they were to remember those in great sorrow and loss.
I read portions of this proclamation as part of my sermon, "The Serious Business of Gratitude," but it's worth reading in its entirety. It is a good way to remember the heart of this holiday and how it might still best be celebrated. Here is the full text :