She has momentum heading into the most important day of the journey to the White House after a substantial victory over Bernie Sanders in South Carolina.
On Sunday she went to the Greater Imani Cathedral of Faith to promise to stamp out racism in America.
Black Christian voters will be the key to a win for Clinton in the race to be Democratic nominee.
"I said last night that it may sound odd from someone running for president, but I think we need more love and kindness," she said to chants of 'yes' from the congregation.
"That should not be reserved for Sunday morning, pastor," she added.
Pastor William Adkins Jr told reporters Mrs Clinton's campaign had asked to attend last week.
"We could not tell anyone. I couldn't even tell my children," Adkins said.
"All I could tell you was: be there Sunday. You don't want to miss it!" He told the Washington Post.
She spoke about the shooting of black people by white police officers and promised to take action to tackle discrimination.