https://www.snopes.com/fact-check/jefferson-injustice-resistance-quote/

Anna Berkes, a manager for public services and collections development at the foundation, wrote in 2013: “This statement has not been found in Thomas Jefferson’s writings, although it captures some of the ideas that Jefferson expressed in the Declaration of Independence, e.g. ‘…when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government…’”