VOICE of a people suffering long,
The pathos of their mournful song,
The sorrow of their night of wrong!
Their cry like that which Israel gave,
A prayer for one to guide and save,
Like Moses by the Red Sea's wave!
The Stern accord her timbrel lent
To Miriam's note of triumph sent
O'er Egypt's sunken armament!
The tramp that startled camp and town,
And shook the walls of slavery down,
The spectral march of old John Brown!
The storm that swept through battle-days,
The triumph after long delays,
The bondmen giving God the praise!
Voice of a ransomed race, sing on
Till Freedom's every right is won,
And slavery's every wrong undone!

John Greenleaf Whittier

http://www.poemhunter.com/poem/the-jubilee-singers/