From H. Leo Boles speech in 1939 when he addressed a unity forum between the Christian church and churches of Christ.
The Lord's people remained a united body from the meeting in Lexington, Ky., in 1832 to 1849. At that time in Lexington my grandfather presented the New Testament teaching for unity. He said, in part, the following:
"God has but one people on the earth. He has given to them but one Book, and therein exhorts and commands them to be one family. A union such as we plead for—a union of God's people on that one Book—must, then, be practicable.
"Every Christian desires to stand complete in the whole will of God. The prayer of the Savior, and the whole tenor of this teaching, clearly show that it is God's will that his children should be united. To the Christian, then, such a union must be desirable.
"But an amalgamation of sects is not such a union as Christ prayed for and God enjoins. To agree to be one upon any system of human inventions would be contrary to his will, and could never be a blessing to the church or the world; therefore, the only union practicable or desirable must be based on the word of God as the only rule of faith and practice... "I have the more cheerfully resolved on this course, because the gospel is a system of facts, commands, and promises, and no deduction or inference from them, however logical or true, forms any part of the gospel of Jesus Christ. No heaven is promised to those who hold them, and no hell is threatened to those who deny them. They do not constitute, singly or together, an item of the ancient and apostolic gospel. While there is but one faith, there may be ten thousand opinions; and, hence, if Christians are ever to be one, they must be one in faith, and not in opinion. When certain subjects arise, even in conversation or social discussion, about which there is a contrariety of opinion and sensitiveness of feeling, speak of them in the words of the Scripture, and no offense will be given and no pride of doctrine will be encouraged. We may even come, in the end, by thus speaking the same things, to think the same things.
"For several years past I have stood pledged to meet the religious world, or any part of it, on the ancient gospel and order of things as presented in the words of the Book. This is the foundation on which Christians once stood, and on it they can, and ought to, stand again. From this I cannot depart to meet any man, or set of men, in the wide world. While, for the sake of peace and Christian union, I have long since waived the public maintenance of any speculation I may hold, yet no one gospel fact, commandment, or promise will I surrender for the world" (Life of Elder John Smith, pages 452-454.)
This is the ground of unity that was accepted in 1832 by the Stone and Campbell groups; it is the fundamental teaching of the New Testament. Such a unity honors the truth of God, respects the authority of Christ, and glorifies God. Brethren, this is where the churches of Christ stand today; it is where unity may be found now; it is where you left the New Testament; it is where you left the churches of Christ, and it is where you can find them when you come back. On this ground and teaching, and only on this, can scriptural unity be had now; on these basic principles of the New Testament Christian unity may always be had. The people of God were united on these principles from 1832 to 1849; they were united on these principles when the church began. Christians enjoyed the sweet fellowship of the people of God and made marvelous progress when so united. They made deep inroads on denominationalism and increased more rapidly in number than at any other period in the history of the Restoration Movement.
for the whole speech, see http://www.therestorationmovement.com/unity1.htm
May the Lord help us find unity in the truth.