SOUTH LOS ANGELES (KABC) -- Thousands of people lined the streets of South Los Angeles for the 32nd annual Kingdom Day Parade in honor of Dr. Martin Luther King Jr. on Monday.The event is billed as the nation's largest and oldest Martin Luther King Jr. Day celebration.Many groups, organizations and elected officials took part in the parade, all celebrating this year's theme: "Now More Than Ever, We All Must Work Together."Los Angeles County Fire Department Chief Daryl Osby, the first African-American chief to hold the post, said King's message and courage to stand up for those in need has inspired him personally and professionally."He talked about civic engagement and to stand up and do what's right for you, your family and your community," Osby said. "That's definitely encouraged me as a human being to stand up and do what's right at all times for myself and my community."Also joining the festivities was Los Angeles County Supervisor Mark Ridley-Thomas, who marched alongside county workers carrying signs that read, "Obamacare works!"Ridley-Thomas, a former grand marshal of the parade, has spearheaded the effort to reopen the Martin Luther King Jr. Community Hospital."[King] stood for health care as a right, not a privilege," he said.Los Angeles County Sheriff Jim McDonnell, who joined the parade on horseback, said he takes to heart King's message of peace."Dr. King's work, we all reflect back on his message that we need to change. We continue to need change. We are constantly evolving, but we need to do it peacefully, work together, bring everybody together as one and make the changes necessary," McDonnell said.The parade began at Martin Luther King Jr. Boulevard and Western Avenue, then rolled west on Martin Luther King Jr. Boulevard before turning south onto Crenshaw Boulevard.The parade lineup featured more than 100 units, including floats, bands, equestrian and dance groups.The parade ended at Vernon Street, where the Freedom Fair was scheduled to take place at Leimert Park after the parade.Legislation was signed in 1983 to create Martin Luther King Jr. Day, which is a federal holiday. Then in 1994, Congress designated the federal holiday as a National Day of Service.