[1][4][8] As an objector to the Burgess Oath, he became the moderator of the Associate Presbytery's Synod, picking the Anti-Burgher side when it later split in the Breach of 1747.
[9] Early accounts state that they worshipped in the open air until 1742, at which point they were able to begin using a church building that they had themselves built in Milnathort, named the "Muckle Kirk".
[9] Small contradicts them, pointing out that contrary to accounts that Mair and his congregation were evicted in 1740, they in fact continued to use the parish church building until 1742, when the General Assembly's attention became drawn to this and it empowered the Presbytery of Dumfermline to enforce their deposition order and "to crave the assistance of the civil power if necessary".
[8] The Muckle Kirk was so named because in addition to it having seating inside for 1200 people (another point where Small, on the basis of what is actually recorded in the manager's books, corrects the earlier authorities who had claimed 2000 people), its hillside location presented a natural amphitheatre at the rear of the building, allowing folding doors to the rear to open out for more congregants to attend services outside.
[9] Mair later came to disagree with the Associate Presbytery over a point of doctrine, and was ejected by the Anti-Burghers in 1755 "as an erroneous person, for maintaining that Christ, in some sense, died for all mankind".
[12][13][9] The point at issue was based upon a Treatise on Justifying Faith that had been written, but never published, by a colleague of Mair's father at Culross, one Fraser of Brae.
[14] Mair's one lasting statement on the matter was the idea of the "common benefits" of Christ's salvation, including "every cup of cold water enjoyed by the unsaved".
[1][16][14] His Covenant of Duties was published posthumously, a series of nine sermons that he had preached years earlier, none of which had any bearing upon the doctrinal point that caused his split with the Anti-Burghers.