What were the purposes of the Bill of Rights and the Declaration of the Rights of Man?

In the most broad of senses, both documents seek to
establish the universal entitlements of all men.  Both arise from the Enlightenment
ideals that that there certain elements that must be endowed to all men because it is
within their natural state of being.  Both documents speak to this truth and establish
an understanding of who individuals are and how their governing bodies must approach
them.  For example, the Declaration of the Rights of Man stresses that individuals
possess an entitlement of freedom of speech and a state of being in the world that
precludes arbitrary arrest.  The Bill of Rights argues the same ideas in constructive
language that firmly embeds such entitlements in the framework of American government. 
In both documents, the reality seeking to be implemented is one where there is a firm
understanding that a sphere to prevent government or external intrusion is
constructed.