Though baptized in the Church of Scotland, and attached to its forms, John Black became, on his arrival in Bovina, an active member of the "Associate Church." This was one of the bodies which afterwards were united and became the "United Presbyterian Church of North America." The minister of the Bovina congregation was Rev. John Graham, a native of Montrose, Scotland, a man of ability, especially as a writer. Before his death he published his "Autobiography," a most interesting book. Of Mr. Graham it was said that he "was a man with eccentricities, but far more excellencies." In Mr. Graham John Black found a true friend, as he did also in the other members of the congregation. True piety prevailed among them. Perhaps some would call them narrow, but they were genuine. They had brought with them from the old land customs such as the regular observance of family worship, the keeping of the Sabbath, and the habit of churchgoing, and these they put into practice in their new world home. As the country settled, many congregations, which are now strong, hived off from the original one in Bovina.
For three years John Black remained a member of this congregation, and his family were very anxious that he should study for the ministry in connection with the Associate Church. He was unable to accept all the views of the Church, however, and this kept him for some time in grave doubt. The Associate Church held that the Scottish covenants were binding on the Church in later times. It will be remembered that these covenants of 1638 and 1643 represent one of the grandest periods in Scottish history. Nobles and people alike, in Greyfriars churchyard, Edinburgh, and elsewhere in Scotland, signed, in some cases with pens dipped in their own blood, the covenant or pledge to oppose prelacy and popery, and to keep the Church of Scotland pure and true. John Black loved and admired the martyrs and Covenanters who fought so nobly for liberty, but he was not sure that two centuries after those stirring times it was still necessary to subscribe these notable documents. The Associate Church required of those who entered its ministry to declare adhesion to "public covenanting," and this threw an obstacle in the way of the young candidate.