The divine institution of the Gospel ministry, and the necessity of episcopal ordination, asserted, by proofs from Scripture, and the practice of the primitive and purest ages of the christian church. In a sermon, Preach'd at the Primary Visitation Of the Right Reverend Father in God, Offspring Blackall, Formerly Lord Bishop of Exon. Held at Okehampton in the County of Devon, Aug. 19, 1709. By William Roberts, M. A. late Rector of Jacobstow in Devon. The fourth edition. Published by his Lordship's Command, and at the Request of the Reverend the Clergy. To which is added, a short character of Dr. George Hooper, formerly Bishop of Bath and Wells. By the Reverend Thomas Coney, D. D. late Rector of Bath