I think that too often people don't think about the pyschological impact of spirituals. I think that people may forget that these 'sorrow songs' were used to build up the morale and will of people living in horrific conditions. Songs like "trouble don't last always" reinforce in people the belief that there can and will be a a better tomorrow on earth, as it is in heaven.

In addition, these spirituals reinforce the believe that there will be consequences-in this life-as well as in the next life {heaven} for those who treat people unjustly. In my opinion, the main message of the "Oh, Mary Don't You Weep" spiritual is that no matter how powerful people or systems are, God is more powerful. In a flash of an eye, these people and these systems who thought they were powerful can be brought down and will face God's justice.

In the "Oh, Mary Don't You Weep" spiritual, a third person tells Mary and Martha not to weep or moan because "a change gonna come". It's important to note that Mary was weeping and her sister Martha was moaning for their own suffering [or, if you use the Biblical story-these sisters were grieving for the death of the brother] and not because the soldiers in Pharoah's army "got drownded". The song seems to imply that they got what they deserved.

And that may have been as far oppressed people could speak truth to power in those days and times. Or maybe its as far as some people can go nowadays for that matter.