Richard Foster in his book "Prayer: Finding the Hearts True Home" describes an aspect of radical prayer as spiritual defiance. He states, "We are subversives in a world of injustice, oppression, and violence. Like Amos of old, we demand that "Justice roll down like waters, and righteousness like an ever-flowing stream" (Amos 5:24). We plead the case of the orphan and the widow, or whoever the helpless ones are in our context." He then goes on to state that we are the voice of the voiceless, pleading their cause and insisting that changes be made.
Foster quotes Walter Wink, "Biblical prayer, is impertinent, persistent, shameless, indecorous. It is more like haggling in an outdoor bazaar than the polite monologues of the churches."
Like Abraham, we bargain with God over the fate of the city (Genesis 18). Like Moses, we argue with God over the fate of the people (Exodus 32). Like Esther, we plead with God over the fate of the nation (Esther 4).
Richard Foster, "Prayer: Finding the Hearts True Home." HarperCollins Publishers. 1992 page 247