Abernethy’s father, also named John, a Presbyterian minister, accompanies Patrick Adair on a deputation from the general committee of Ulster presbyterians, who present a congratulatory address to William III in London in 1689, and obtain from the king a letter (November 9, 1689) recommending their case to Meinhardt Schomberg, 3rd Duke of Schomberg.
At the age of 13, Abernethy enters the University of Glasgow and, upon concluding his course there, goes on to the University of Edinburgh, where he soon moves in the most cultured circles. Returning home, he is licensed to preach from his Presbytery before he is twenty-one. In 1701 he is called to accept charge of an important congregation in Antrim. After an interval of two years, mostly spent in further study in Dublin, he is ordained there on August 8, 1703. He becomes a noted debater in the synods and assemblies of his church and a leading evangelist. He has been described as being at this time “the young minister of Antrim … a man of studious habits, heretical opinions, and remarkable ability.”
In 1712, he is devastated by the loss of his wife, Susannah Jordan. Five years later, he is invited to the congregation of Usher’s Quay, Dublin, and also to what is called the Old Congregation of Belfast. The synod assigns him to Dublin. After careful consideration he refuses and remains at Antrim. This refusal arouses disapproval and a controversy follows, with Abernethy standing firm for religious freedom and repudiating the ecclesiastical courts. The controversy and quarrel bears the name of the two camps in the conflict, the “Subscribers” and the “Non-subscribers.” Abernethy and his associates sow the seeds of the struggle (1821–1840) in which, under the leadership of Dr. Henry Cooke, the Arian and Socinian elements of the Presbyterian Church in Ireland are thrown out.
Much of what Abernethy contends for, and which the “Subscribers” oppose bitterly, is silently granted in the lapse of time. In 1726, the “Non-subscribers” are cut off, with due ban and solemnity, from the Presbyterian Church of Ireland. In 1730 he moves to Wood Street, Dublin. It is said of him that, although a “Non-subscriber,” he is a Trinitarian. However, Dr. Cooke states that Arianism “made very considerable progress under the patronage of high names, as Abernethy, the author of a very excellent work upon the Attributes, who gave it a great deal of eclat.”
In 1731 comes the greatest controversy in which Abernethy is involved. It is nominally about the Test Act, but actually on the entire question of tests and disabilities. His stand is against all laws that, upon account of mere differences of religious opinions and forms of worship, exclude men of integrity and ability from serving their country.
Abernethy is nearly a century in advance of his age. He has to reason with those who deny that a Roman Catholic or Dissenter can be a “man of integrity and ability.”
John Abernethy dies on December 1, 1740.