An article from Wikipedia describes this song as, a Negro spiritual that originates from before the American Civil War– thus it is what scholars call a "slave song," "a label that describes their origins among the enslaved," and it contains "coded messages of hope and resistance." It is one of the most important of Negro spirituals.
The song tells the Biblical story of Mary of Bethany and her distraught pleas to Jesus to raise her brother Lazarus from the dead. Other narratives relate to The Exodus and the Passage of the Red Sea, with the chorus proclaiming, “Pharaoh's army got drown-ded!”, and to God's rainbow covenant to Noah after the Great Flood. With liberation thus one of its themes, the song again become popular during the Civil Rights Movement.
The following video is from Dust-to-Digital:
Travel back to Augusta, Georgia in 1929:
A group of farm workers singing the spiritual, "Mary, Don't You Weep."
Thanks to the University of South Carolina for preserving this rare footage.