Thanks, Mooh. I found out that the composer is Oscar Peterson.

See this quote:

"Hymn to Freedom

In 1962, Oscar Peterson composed the Hymn to Freedom, a song with deep musical meaning and cultural importance. Inspired by Martin Luther King's movement during the social upheaval of the 1960s, Oscar composed the Hymn to Freedom to protest against segregation and racism, and advocate liberty and equality for all.

This effort at composition made its debut on the Oscar Peterson Trio album, Night Train (Verve 1962) with Ray Brown on bass, and Ed Thigpen on drums. It has subsequently become one of Peterson's most acclaimed compositions and has appeared on several of his albums. Its popularity continued into the 1980s, when other versions were recorded by Oliver Jones and Doug Riley.

Proof of the hymn's endurance and universal quality came in 1986, when 10 children's choirs from around the world met in Helsinki, Finland, for the International Choral Sympaatti (the biggest international festival for children's choirs ever organized in Finland), and performed a special version of ."
   

Also, this website has a sound clip but no lyrics.

http://www.collectionscanada.ca/oscarpeterson/m3-6030-e.html