The _Millennial Harbinger_ appeared monthly from 1830 to 1870. Mr. Campbell was its editor for nearly thirty years. During this time it was the backbone of Disciples' periodical literature. A great many small monthlies very soon began to spring up. Most of them had small circulation and short life, but their total influence was great, and a few became important. A list printed in 1845, and not claiming to be complete, names fifteen monthlies and two weeklies in existence at that time.
The union between the Disciples and the Christian churches in Kentucky and adjacent states west of the Alleghenies was an event of the utmost importance for the whole movement. Since the churches of both groups exercised a high degree of local independence, union could not have been brought about by any binding act of conferences or conventions, even if there had been general conferences or conventions in either party, as there were not. It had to depend upon a contagion of fellowship between their congregations in many communities. But the process was rapid, and the union may be dated as of 1832. It began with a consultation among some of their leaders on the first day of that year and was far enough advanced to insure its success before the end of the year.
Barton W. Stone and Alexander Campbell first met in 1824. They were friends from the start, and both were impressed by the similarity of their pleas for simple and evangelical Christianity. In 1826 Mr. Stone began the publication of a monthly, the _Christian Messenger_, at Georgetown, Kentucky. In a communion having no general organization and no cooperative work, it was his position as editor which, more than anything else, gave him the prominence that has led to calling the Christian church in Kentucky, not very accurately, "the Stone movement." Since he wrote constantly and copiously for his magazine and also published reports of the activities of the churches and evangelists, it gives a good contemporary picture of his mind and of the principles and practices of the Christian churches during the years immediately before the union.
The unity of all Christians was the theme of a series of articles which began in the first issue of the _Christian Messenger_, and the topic frequently recurs. Stone gives the arguments for unity and states and answers the possible objections. The principal obstacle to union, as he sees it, is insistence upon doctrinal agreement. Stone is for tolerance on all matters of opinion. Yet there are some doctrines in the orthodox creeds which Stone considers so erroneous that he is not content to say that they ought not to be made tests of fellowship; he must try to disprove them and eliminate them from the minds of all Christians. These are the generally accepted doctrines of the Trinity, the nature of Christ, and the atonement. Upon each of these subjects Mr. Stone wrote many long articles and editorials. He did not hesitate to say that "we deny the Trinity," not because it is mysterious but because it is not a revealed doctrine. The character of God is revealed, but not his essence or the mode of his existence. Christ was the Son of God, being of the same nature but not of the same substance. The Holy Spirit "means the power or energy of God, never a third person in deity."