Robert Barclay was one of the sventeenth century’s greatest Quaker theologians and willing to suffer for the faith. He held that the only real Christianity is that in which the Spirit of Christ is present and he rejected any faith that rested on history, liturgy, or doctrinal statements without inner life. He went to prison at least twice for his teachings. In January 1677 he wrote a treatise on universal love while in Abderdeen prison where he was kept. He was held for about five months that time in conditions that were sometimes crowded with little air and less light. In 1679 he was committed to prison again, but held for only a few hours.
As might be expected, he opposed persecution and argued that state authorities have no right to punish people for their conscientious views considering that only God has power over conscience.