With this year’s publication of “The Passage of Power,” the fourth installment in his biography of President Lyndon Baines Johnson, Robert Caro revisits the fateful days in 1963 after the assassination of President John F. Kennedy thrust LBJ into the Oval Office.

The assassination unfolded on Nov. 22 that year, just days before the national observance of Thanksgiving. That Thanksgiving Day — Nov. 28, 1963 — was a strange one for the country. Americans were still in shock about what had transpired in Dallas, and they remained unsure about what would happen under the leadership of their new president.

Johnson had addressed Congress on the day before Thanksgiving, pledging resolve and continuity in the midst of crisis. The observance of Thanksgiving that year was, in itself, a symbol of solemn continuity for the country. A shadow fell over the holiday, but the recognition of Thanksgiving was a sign that the country’s underlying civic traditions remained strong. That’s why national customs like Thanksgiving are so important. They provide the stability of tradition, a great source of stability in periods of stressful challenge and change.

Johnson addressed the nation again on Thanksgiving Day 1963.

“On this Thanksgiving Day, as we gather in the warmth of our families, in the mutual love and respect which we have for one another, and as we bow our heads in submission to divine providence, let us also thank God for the years that He gave us inspiration through his servant, John F. Kennedy,” Johnson told his fellow Americans. “Let us today renew our dedication to the ideals that are American. Let us pray for His divine wisdom in banishing from our land any injustice or intolerance or oppression to any of our fellow Americans whatever their opinion, whatever the color of their skins — for God made all of us, not some of us, in His image. All of us, not just some of us, are His children.”

Johnson’s words continue to ring with urgency on this Thanksgiving, as Americans confront other divisions and other challenges. His message is worth heeding as the nation begins another holiday season.