The following year, Boyd moved from Macosquin to a congregation nearer Londonderry (formerly known as Taughboyne and later as Monreagh), where he was installed by the Derry presbytery on 25 April 1725 at a stipend of £50l.
His sermon was directed especially against a discourse by the non-subscribing minister of the town in which it was delivered: John Abernethy, M.A., whose "Religious Obedience founded on Personal Persuasion" was preached at Belfast on 9 December 1719 and published in 1720.
Boyd decided that "conscience is not the supreme lawgiver" and that it has no judicial authority, except insofar as it administers "the law of God": an expression which (to him) was synonymous with the interpretation of scripture accepted by his church.
His zeal for the faith was again shown in 1739, when he took the lead against Richard Aprichard, a probationer of the Armagh presbytery (who had scruples about some points of the Confession, and ultimately withdrew from the synod's jurisdiction).
Boyd published only "A Good Conscience, a Necessary Qualification of a Gospel Minister: a Sermon on Hebrews 13:18 Preached at Antrim on 15 June 1731 at a General Synod of the Protestants of the Presbyterian Persuasion in the North of Ireland" in Derry in 1731.