President Barack Obama joined with lawmakers on Capitol Hill on 9 December to mark the 150th anniversary of the 13th Amendment, which ended slavery in the US.
"We betray the efforts of the past if we fail to push back against bigotry in all its forms," Obama said.
The president also appeared to reference modern day racial disparities with regard to law enforcement. "We would do a disservice to those warriors of justice, [Harriet] Tubman and [Frederick] Douglass and [Abraham] Lincoln and [Martin Luther] King, were we to deny that the scars of our nation's original sin are still with us today."
The 13th Amendment outlawed slavery. The 14th Amendment granted citizenship to former slaves. "Our freedom is bound up in the freedom of others, regardless of what they look like or where they come from or what their last name is or what faith they practice," he said.
His remarks come just days after presidential candidate Donald Trump, who leads opinion polls in the Republican nomination race, called for a block on Muslims entering the country following the shootings in California by two individuals who authorities said were radicalised.