“By 1776, Jefferson was one of the largest planters in Virginia. However, the value of his property (land and slaves) was increasingly offset by his growing debts, which made it very difficult to free the people he kept forced in to slavery, and thereby lose them as assets.
“In his writings on American grievances justifying the Revolution, he attacked the British for sponsoring human trafficking to the colonies.
“In 1778, with Jefferson’s leadership, slave importation was banned in Virginia, one of the first jurisdictions worldwide to do so.
“Jefferson was a lifelong advocate of ending the trade and as president led the effort to criminalize the international slave trade that passed Congress and he signed in 1807, shortly before Britain passed a similar law.
“In 1779, as a practical solution to end the legal enslavement of humans, Jefferson supported gradual emancipation, training, and colonization of African-American slaves rather than unconditional manumission, believing that releasing unprepared people with no place to go and no means to support themselves would only bring them misfortune.
“In 1784, Jefferson proposed federal legislation banning slavery in the New Territories of the North and South after 1800, which failed to pass Congress by one vote.
“In his Notes on the State of Virginia, published in 1785, Jefferson expressed the beliefs that slavery corrupted both masters and slaves alike, supported colonization of freed slaves, promoted the idea that African-Americans were inferior in intelligence, and that emancipating large numbers of slaves made slave uprisings more likely.
https://en.wikipedia.org/wiki/Thomas_Jefferson_and_slavery
Learned about that when I visited Monticello last month (lovely, gorgeous day and I saw James Monroe’s Highland later that afternoon). Jefferson saw to it that his slaves learned important trades so they could get jobs after they were freed in his will.