 In 1797, and again in 1801, he was elected Donnellan Lecturer, his subject being "The Divine Origin of the Jewish Religion, proved from the internal evidence of the last four Books of the Pentateuch".His lectures, "Graves on the Pentateuch", for which he is best remembered, were first published in London in 1807, in two octavo volumes, while he was serving as chaplain to the Duke of Richmond, Lord Lieutenant of Ireland.The work was widely acclaimed and was for many years studied by divinity students at English, Irish and American universities, and the university of Calcutta too.