Samuel Rutherford's favourite correspondent was, to begin with, a woman of quite remarkable powers of mind. We gather that impression powerfully as we read deeper and deeper into the remarkable series of letters that Rutherford addressed to her. To no one does he go into deeper matters both of Church and State, both of doctrinal and personal religion than to her, and the impression of mental power as well as of personal worth she made on Rutherford, she must have made on many of the ablest and best men of that day. Robert Blair, for instance, tells us that when he was on his way home from London to Ireland he visited Scotland chiefly that he might see Rutherford at Anwoth and Marion M'Naught at Kirkcudbright, and when he came to Kirkcudbright he found Rutherford also there. And when Rutherford was in exile in Aberdeen, and in deep anxiety about his people at Anwoth, he wrote beseeching Marion M'Naught to go to Anwoth and give his people her counsel about their congregational and personal affairs. But, above all, it is from the depth and the power of Rutherford's letters to herself on the inward life that we best gather the depth and the power of this remarkable woman's mind. There is no other subject of thought that gives such scope for the greatest gifts of the human mind as does the life of God in the soul. There is no book in all the world that demands such a combination of mental gifts and spiritual graces to understand it aright as the Bible. The history and the biography of the Bible, the experimental parts of the Bible, the doctrines of grace deduced by the apostles out of the history and the experience recorded in the Bible, and then the personal, the most inward and most spiritual bearing of all that,--what occupation can be presented to the mind of man or woman to compare with that? True religion, really true religion, gives unequalled and ever-increasing scope for the best gifts of mind and for the best graces of heart and character. 'In truth, religious obedience is a very intricate problem, and the more so the farther we proceed in it.' And he has poor eyes and a poor heart for true religion, and for its best fruits both in the mind and the heart and the character, who does not see those fruits increasing letter by letter as Rutherford writes to Marion M'Naught.