Well for one thing, some of Jefferson's writings are so closely paraphrased from John Locke it borders on plagiarism. Indeed, the two documents are so similar that it's not hard to imagine Jefferson looking over his annotated copy of "Two Treatises of Government" as he drafted the Declaration of Independence.
Where Locke said we had "insuperable rights" of "life, liberty and property", Jefferson said we had "inalienable rights" of "life, liberty, and the pursuit of happiness".
Locke also appears to have been the source of many of Jefferson's core principles, such as "consent of the governed" and the role of revolutions as a last resort---but a necessary option to have---against tyranny.
Oddly, Jefferson did not actually speak or write about Locke specifically all that often, but he seemed to deeply internalize most of Locke's ideas on political philosophy. It could be what is called "the anxiety of influence"; perhaps Jefferson knew that he was so influenced by Locke that if he talked about Locke too much people would think he had no new ideas of his own!