WASHINGTON — Never before has one president eulogized another who was also his father. In 1826, President John Quincy Adams did not learn his father, John Adams, the second president, had died until after he had been buried.

"Through our tears, let us know the blessings of knowing and loving you, a great and noble man. The best father a son or daughter could have," said former President George W. Bush as he eulogized his father Wednesday.

For a moment, through a choked back sob, the son sounded like any man bidding his father farewell. But not just any man could say this: "He showed me what it means to be a president who serves with integrity, leads with courage and acts with love in his heart for the citizens of our country."

Former President George W. Bush speaks at the state funeral for his father, former President George H.W. Bush, at the National Cathedral, on Dec. 5, 2018, in Washington, D.C. Getty

The Bushes are only the second father and son to both serve as president in U.S. history. The bond between George H.W. Bush and his eldest son was cemented in private moments. It was strengthened publicly through military service, on the campaign trail and in the Oval Office.

"Being a child of a president is unpleasant," George W. Bush told "60 Minutes." "I mean, you watch somebody you love get lampooned, or made fun of, or harshly criticized. It hurts."

George H.W. Bush's losing bid for re-election planted a seed for his sons.

"It's not a scheme, it's not a dynasty, it's not a legacy, but would Barbara and I be proud," George H.W. Bush said.

But his children say they didn't need lofty titles to have their father's love.

"He encouraged and comforted but never steered. We tested his patience, I know I did. But he always responded with the great gift of unconditional love," George W. Bush said in his eulogy.

Especially in moments of need. Three days after the 9/11 attacks, a shaken commander in chief mourned the dead and returned to his cathedral pew, to find the comforting hand of a father who knew the burdens of the office. On Wednesday, he made the same walk, with his own hand reaching out.