The most important Enlightenment influences on these two documents were John Locke and Montesquieu, respectively.
John Locke had a tremendous influence on the ideas and words that Thomas Jefferson used in the Declaration of Independence. He argued that government was only valid if it had the consent of the people. He argued that its only proper purpose was to protect people’s basic rights. These rights were, in his terms, life, liberty, and property.
Montesquieu had an important influence on the Constitution. His most important idea was the idea of the separation of powers. He argued that it was important for a government’s powers to be divided between separate judicial, executive, and legislative branches.
In these ways, the major ideas of these documents came from Locke and Montesquieu, respectively.