Six letters to the Rev. Mr. George Whitefield : The first, second, and third, on the subject of justification. The fourth containing remarks on a pamphlet, entitled, The case between Mr. Whitefield and Dr. Stebbing stated, &c. The fifth containing remarks on Mr. Whitefield's two letters concerning Archbishop Tillotson, and the book entitled, The whole duty of man. The sixth, containing remarks on Mr. Whitefield's second letter, concerning Archbishop Tillotson, and on his letter concerning the Negroes. /