John Howie, The Scots Worthies, pp. 435-436:
Soon after having obtained his license, Guthrie left St. Andrew's, and became tutor to lord Mauchlin, eldest son to the earl of London, in which situation he remained until appointed pastor to the parish of Fenwick, which at that time was disjoined from Kilmarnock. Having been appointed to preach at Galston, on a day preparatory to the celebration of the Lord's Supper, and a number of persons belonging to the newly erected parish being present, they were so much captivated by his discourses, that they immediately resolved to call him to be their pastor, which being very harmonious, he felt it to be his duty to accept. It is said that he, along with the people, made choice of the spot of ground on which the church was to be built, and that he preached within the walls before the edifice was completely finished.
Many were the difficulties and discouragements he had to encounter at the outset; yet through the divine blessing upon his labours, he was eminently successful in reforming the manners of the people. Many of them, indeed, were so unconcerned about religion as never to enter a place of worship; and the face of their pastor was altogether unknown by them. Numbers even refused his visits, and would not suffer him to enter their houses. Such was the state of Fenwick at the time this pious man entered upon his ministerial duties among them. But things did not remain long in that state; for, he had a happy art of winning souls to the Saviour. Disguised in the habit of a traveller, he frequently called at their houses in the evening, and asked lodgings, which he did not even obtain without much entreaty; but, when once admitted, he made himself a very agreeable guest, by his amusing and instructive conversation. One question always was,—how did they like their minister?—and when told that they did not go to church, he pressed them to go, and hear what he had to say. To some he even gave small sums of money to visit the house of God; and, before retiring to rest for the night, he was always solicitous to know if family worship was observed by them.
Upon one occasion, in a family where the duty had never been performed, he urged the goodman of the house to make the attempt; and, as this person's only objection was, that he could not pray, that he had never been in the habit of praying, and therefore could not, Gnthrie was so very earnest in his entreaties to make trial, that the man cried out:—"O Lord, thou knowest that this man would have me to pray; but thou knowest I cannot pray!" This was sufficient, —Guthrie desired him to stop, saying, he had done enough, and immediately began himself, to the great wonder and edification of the family. When prayer was over, the mistress of the house said to her husband—"Surely this man must be a minister." The people were overawed, and felt as if a charm had come over them. It was no difficult matter, under such feelings, to gain their compliance to appear in church on the following Sabbath. But, what was their surprise, when they saw that it was the minister himself who had been their guest, and who, in the guise of an humble peasant, upon their own hearth, had supplicated for them so many blessings.
Within his parish, too, there was a person who, instead of going to church on the Lord's day, betook himself to the fields with his dog and gun. Guthrie was determined to reclaim this man, and the effort was blessed. The minister asked him what reason he had for desecrating the Sabbath; and the answer he received was, that it was the most fortunate day in the week for that exercise. Guthrie asked him how much he could make by it; and, upon being told that he could at least realize half a crown, the good pastor at once told him that he would pay him that sum, if he would appear in church next Sabbath. After the congregation was dismissed, Guthrie told him that he would renew the bargain, if he would appear again, which the man consented to do. From that time afterward, he never failed to give regular attendance in the house of God; and, relieving the minister from his obligation, he felt to his sweet experience that godliness was of itself great gain. This man, ere long, became a member of the kirk-session, and ever after continued to live a godly and useful life.