It is a great quote but slightly out of context as presented. It is from a letter to B. Rush in 1800 that attacks the clergy. Here is a better representation of Jefferson's intent: "The returning good sense of our country threatens abortion to their hopes, and they [the clergy] believe that any portion of power confided to me, will be exerted in opposition to their schemes. And they believe rightly; for I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. But this is all they have to fear from me: & enough too in their opinion, & this is the cause of their printing lying pamphlets against me. . ."