The Rev. Al Sharpton and his supporters chanted "Get on the bus" Saturday morning at his Harlem headquarters as he renewed his call for a march on the nation's capitol to protest the grand jury decision in the Eric Garner case.

Members of Garner's family also took to the podium and voiced appreciation for the efforts of protesters, urging them to continue to keep up the nonviolent movement.

Thousands of people have protested in the streets, landmarks and stores of New York City and other locations nationally for the past four days in response to a grand jury's decision not to indict NYPD Officer Daniel Pantaleo in the apparent chokehold death of Garner during an arrest on July 17.

"This is a movement of all races and ages," Sharpton said. "It is very heartwarming to see that across this country -- with no violence -- [people are] speaking out for Eric Garner, Trayvon Martin and Michael Brown."

Sharpton said that on Dec. 13 the families of all three men will be "leading the march, their arms locked together all heading down Pennsylvania Avenue."

Both Garner's mother and widow told the audience Saturday they were thankful for "all the peaceful protesters" who came out for Eric Garner.

"You, the protesters, have stood with me. You are standing up for my son. My heart is overflowing with joy. It is a gracious feeling," said Gwen Carr, Garner's mother-in-law.

Esaw Garner also spoke, calling her late husband "a gentle giant."

"Everyone who knew my husband knew he was a good man and the enormity of the love he gave to everyone," she said.

Sharpton told the audience to sign up for the march next weekend; buses are planned that will leave from his National Action Network headquarters on 145th Street and from the site of Garner's death in Staten Island.

Filmmaker and advocate Spike Lee and Corey Wise, one of the five men wrongfully convicted in the 1989 Central Park jogger case, were present at the event.

With Candice Ferrette