John Locke is a major architect of our American system of government, whose designs were followed a century later by Madison and the Founders in building our system.

John Locke argued against the exercise of any governmental effort to promote or to restrict particular religious beliefs and practices. Freedom of religion must never be used as a club to coerce other people; rather, respect the beliefs of all others. This thought Madison called "establishment" of religion.

One of Locke's major writings is at this link: http://www.constitution.org/jl/tolerati.htm  — A Letter Concerning Toleration that begins: “Since you are pleased to inquire what are my thoughts about the mutual toleration of Christians in their different professions of religion, I must needs answer you freely that I esteem that toleration to be the chief characteristic mark of the true Church. For whatsoever some people boast of the antiquity of places and names, or of the pomp of their outward worship; others, of the reformation of their discipline; all, of the orthodoxy of their faith — for everyone is orthodox to himself — these things, and all others of this nature, are much rather marks of men striving for power and empire over one another than of the Church of Christ." Is this a fair summary: Christians in their very differences must be tolerated — all at the same level.

Locke wrote about government as it should be to support human rights: http://www.sparknotes.com/philosophy/johnlocke/section2.rhtml — Spark Notes summary of Locke’s Two Treatises of Government that argue against the divine right of kings; he then urges his philosophy of government.

Locke’s second Treatise of Government in various formats:
http://oll.libertyfund.org/?option=com_staticxt&staticfile=show.php%3Ftitle=222

Most of John Locke's writings are available on iPad, Kindle, and other platforms.

John Locke's life and involvement in political movements led to he and friends fleeing England for a while; read about his interesting life. He wrote a variety of books, including commentaries on the letters of St. Paul.

My chart of the Enlightenment thinkers' shows their relationship chronologically. They published their writings, which were read by other Enlightenment philosophers.