But the time had come for a complete change in the tone and tenour of David Barclay's life. He had gained renown and position, and had allied himself with a branch of the Royal family, but these had brought him neither peace nor satisfaction. Royal blood is no guarantee against disease and death, and he had had to see his beloved wife fade away and die at the early age of forty-three. He had risked limb and life, and had striven with hand and brain to win renown, and position, and wealth, only to find that these things expose their possessor to special trials and dangers. He had found out by hard experience how uncertain was his tenure of earthly good. His sorrows and disappointments prepared his heart for more earnestness about spiritual truth than he had hitherto manifested, and Quakerism was to present that truth in a form which would satisfy his mind and heart.
Perhaps it was whilst on the journey to fetch home his son, that he became closely acquainted with the Quakers. He tells us how he had heard of their simple and conscientious living, and "he considered within himself that if they were really such as even their enemies were forced to acknowledge, there must be something extraordinary about them." Whether or not this knowledge was gained in Aberdeen, where a meeting had been gathered now more than a year, we do not know. But, "being in London" on some errand or other, he had opportunities to enquire into the Quaker principles and practises, which he did to such purpose, that his mind became convinced that their tenets were according to the Scriptures. Still, the cautious Scotchman did not immediately join them.
Immediately afterwards we find David Barclay in prison in Edinbro' Castle. Although he had suffered for the king, he was accused of having held office under Cromwell, and it might have gone hardly with him had he not been befriended by his old chief, the Earl of Middleton. Through the influence of that nobleman the proceedings were quashed, and he was liberated.
This imprisonment, in the ordering of God's providence, brought to the right issue the great crisis of his life. In the same room with him in Edinbro' Castle was imprisoned Sir John Swintoune, who from a soldier and a Presbyterian had become a thorough Quaker. He was so zealous in propagating his opinions that the only way to silence him was to keep him in solitary confinement, which was at one time done for several weeks. No wonder, then, that he urged on David Barclay the full acceptance of the truth.