Under the law of nature, all men are born free, every one comes into the world with a right to his own person, which includes the liberty of moving and using it at his own will. This is what is called personal liberty, and is given him by the author of nature, because necessary for his own sustenance.
In Blair v. Blair, Jefferson was asked to to look at the possibility of doing something never tried in Virginia before: a divorce. The marriage between Dr. James Blair, of Williamsburg, and Catherine "Kitty" Eustace, of New York, dissolved quickly amid rumors of Blair's "incompetence" and an affair between Kitty Blair and the governor, John Murray, Earl of Dunmore.
Dr. Blair retained Jefferson to obtain a divorce for him. The problem confronting Jefferson in his representation of Blair was daunting, largely by reason of the fact that a divorce had never been granted in the 155 years that Virginia had been in existence. In order to obtain the result that his client wanted, Jefferson would have to challenge the very foundations of the laws of the colony. "His research went beyond divorce: it entailed the very relationship of an empire and its colonies and whose law should govern. The Blair case was a test of his emerging theory of self-rule for Virginia." William Sterne Randall, Thomas Jefferson - A Life, at 201(1993, Harper Perennial) at 163. Jefferson sought to apply the "...natural rights to the laws of marriage as he had to the relationship between slave and master and church and state." As he was to do later in the Declaration of Independence, Jefferson looked to the writings of Hume, Locke and Montesquieu. Id. at 164. This laid the groundwork for Jefferson to examine as a student of the Enlightenment the natural right of man to terminate relationships whether they be they master and slave, husband and wife, or Great Britain and the colonies. Unfortunately, Jefferson was never to make these arguments since Dr. Blair died.
It was from cases like these that Jefferson would write in the Declaration of Independence about "the Laws of Nature and of Nature's God." Jefferson later wrote about how, when he wrote summaries, he "sometimes mix[ed] my own reflections on the subject … [T]hey were written at a time of life when I was bold in the pursuit of knolege, never fearing to follow truth and reason to whatever results they led, & bearding every authority which stood in their way." Jefferson to Dr. Thomas Cooper, February 10, 1814.