One thing I do well remember about Mateer: his mental superiority impressed everyone, as also his deep spirituality. In some respects, indeed most, he stood head and shoulders above his fellows around him.
Another classmate, Rev. Dr. William Gaston, of Cleveland, says:
We regarded him as one of our most level-headed men; our peer in all points; not good merely in one point, but most thorough in all branches of study. He was cheerful and yet not flippant, and with a tinge of the most serious. He was optimistic, dwelling much on God’s great love.... He was not only a year in advance of most of us in graduating from college, but I think that we, as students, felt that though we were classmates in the seminary, he was in advance of us in other things. Life seemed more serious to him. I doubt if any one of us felt the responsibility of life as much as he did. I doubt if anyone worked as hard as he.
The Western Theological Seminary, during the period of Mateer’s attendance, was at the high-water mark of prosperity. The general catalogue shows an enrollment of sixty-one men in his class; the total in all classes hovered about one hundred and fifty. In the faculty there were only four members, and, estimated by the specializations common in our theological schools to-day, they could not adequately do all their work; and this was the more true of them, because all save one of them eked out his scanty salary by taking charge of a city church. But they did better than might now be thought possible; and especially was this practicable because of the limited curriculum then prescribed, and followed by all students. Dr. David Elliott was still at work, though beyond the age when he was at his best. Samuel J. Wilson was just starting in his brilliant though brief career, and commanded a peculiar attachment from his pupils. Dr. Jacobus was widely known and appreciated for his popular commentaries. However, the member of the faculty who left the deepest impress on Mateer was Dr. William S. Plumer. Nor in this was his case exceptional. We all knew that Dr. Plumer was not in the very first rank of theologians. We often missed in his lectures the marks of very broad and deep scholarship. But as a teacher he nevertheless made upon our minds an impression that was so great and lasting that in all our subsequent lives we have continued to rejoice in having been under his training. Best of all was his general influence on the students. We doubt whether in the theological seminaries of the Presbyterian Church of the United States it has ever been equaled, except by Archibald Alexander of Princeton. The dominant element of that influence was a magnificent personality saturated with the warmest and most tender piety, having its source in love for the living, personal Saviour. For Dr. Plumer, Mateer had then a very high degree of reverent affection, and he never lost it.
Spiritually, the condition of the seminary while Mateer was there was away above the ordinary. In the winter of 1857-58 a great revival had swept over the United States, and across the Atlantic. In no place was it more in evidence than in the theological schools; it quickened immensely the spiritual life of the majority of the students. One of its fruits there was the awakening of a far more intense interest in foreign missions. I can still recall the satisfaction which some of us who in the seminary were turning our faces toward the unevangelized nations had in the information that this strong man who stood in the very first rank as to character and scholarship had decided to offer himself to the Board of Foreign Missions for such service as they might select for him. It was a fitting consummation of his college and seminary life.
Yet it was only slowly, even in the seminary, and after much searching of his own heart and much wrestling in prayer, that he came to this decision. Outside of himself there was a good deal that tended to impel him toward it. The faculty, and especially Dr. Plumer, did all they could wisely to press on the students the call of the unevangelized nations for the gospel. Representatives of this cause—missionaries and secretaries—visited the seminary, where there were, at that time, more than an ordinary number of young men who had caught the missionary spirit. In college, Mateer, without seeking to isolate himself from others, had come into real intimacy with scarcely any of his fellow-students. He says in the autobiographical sketch, “I minded my own business, making comparatively few friends outside of my own class, largely because I was too bashful to push my way.” In the seminary he, while still rather reserved, came nearer to some of his fellow-theologues; and especially to one, Dwight B. Hervey, who shared with him the struggle over duty as to a field of service. They seem to have been much in conference on that subject.
On the 21st of January, 1860, he presented himself before the Presbytery of Ohio, to which the churches of Pittsburg belonged, passed examination in his college studies, and was received under the care of that body; but he had not then made up his mind to be a missionary. On the 12th of April of the same year he went before the Presbytery of Butler, at Butler, Pennsylvania (having at his own request been transferred to the care of that organization, because his parents’ home was now within its bounds), and was licensed to preach. Yet still he had not decided to be a missionary. He was powerfully drawn toward that work, and vacillation at no time in his life was a characteristic; there simply was as yet no need that he should finally make up his mind, and he wished to avoid any premature committal of himself, which later he might regret, or which he might feel bound to recall.
The summer of 1860 he spent in preaching here and there about Pittsburg, several months being given to the Plains and Fairmount churches; followed by a visit home, and another in Illinois.
When the seminary opened in the autumn, he was back in his place. One of the duties which fell to him was to preach a missionary sermon before the Society of Inquiry. He did this so well that the students by vote expressed a desire that the sermon should be published. In his Journal he notes that the preparation of this discourse “strengthened his determination to give himself to this work.” Before the Christmas recess Dr. J. Leighton Wilson, one of the secretaries of the Presbyterian Board of Foreign Missions, visited the seminary, and in conference did much to stimulate the missionary spirit. He found in Mateer an eager and responsive listener. On the 12th of December Mateer wrote a long letter to his mother, in which he expresses feeling, because without warrant some one had told her that he had offered himself to the Foreign Board. He says, “I am not going to take such an important step without informing you of it directly and explicitly.” Then he proceeds to tell her just what was his attitude at that time: