Those events, Biden said, "laid the groundwork for other milestones of freedom to follow."
Biden cited the "constant march in America" for more freedoms: the Voting Rights Act of 1965, the Age Discrimination in Employment Act of 1967, the Fair Housing Act of 1968, the Americans with Disabilities Act of 1990 and Title IX, the 1972 law on gender equity in education.
"As well as finally the civil-rights issue of our day, making it clear you should be able to marry whoever you love, period," Biden said of the June 2013 Supreme Court ruling overturning the 1996 Defense of Marriage Act.
"Ladies and gentlemen, ultimately that's what we're celebrating today: the continuation of the expansion of the notion that all men are created equal."
That work, Biden added, is not complete.
"But the landmark events we celebrate today make it clear that the narrow-minded and reactionary forces of the past and the present will never prevail in America," Biden said.
Mayor Nutter, speaking before Biden, pointed to the continuing struggle to fund public schools in the city as the "civil-rights issue of the 21st century." He noted that the Brown v. Board of Education ruling declared "separate but equal" education, segregated by race, to be unconstitutional.
"Across our commonwealth, school districts are struggling under the burden of inadequate and unfair funding, unable to properly prepare our young people for the world of tomorrow," Nutter said. "Separate but underfunded is unfair, it is wrong also."
On Twitter: @ChrisBrennanDN