What was the historical background to their discussion? According to Lester G. McAllister and William E. Tucker, young Alexander Campbell and other reformers of the early first generation defended "close communion," which in their circles meant "the practice of admitting only believers baptized by immersion to the service of Communion." By contrast, Barton W. Stone and like-minded Christians in Kentucky did not forbid "defective believers" from participating in the Lord's Supper. Eventually, Campbell's outlook changed and his position moved closer to the one held by Stone.
As Campbell moved into maturity, he modified his view and joined some of the followers in shifting from close to open communion. The impulse to reflect the oneness of God's people around the Lord's Table was stronger than the will to hold fast to an exclusivist interpretation of New Testament Christianity. Such were the competing principles with which the first and all subsequent generations of restorationists have had to grapple. Is the Restoration Movement primarily motivated by Christian unity or doctrinal purity? Or, as McAllister and Tucker put it, "Is the church primarily an inclusivist or an exclusivist community?" 
Before examining the specific comments of Errett, Richardson, and Pendleton about the Lord's Supper, it would be best to establish the specific context in which they were written. Apparently, the three responses were occasioned by a letter from a certain "Bro. Hawley." According to Richardson's reply, a discussion had emerged "among the brethren in Detroit in regard to the question of open or close communion." The reference to Detroit provides an important clue. It is most likely that the author was Richard Hawley (1815?-1884). He attended the inaugural, 1849 meeting of the American Christian Missionary Society in Cincinnati and was elected one of its officers. Among the officers of the ACMS, he served as one of twenty vice presidents, who were geographically distributed. Hawley represented Disciples in the State of Michigan. 
"Bro. Hawley," as his name appears, sent the same letter or a similar one to both Errett and Richardson, who then responded in the pages of the Harbinger. W. K. Pendleton, then a co-editor of the magazine, also offered his reflections on the issues.
In his response written from Muir, Michigan, Isaac Errett began by acknowledging that the plea of the present reformation was to bring back the conditions that presumably existed among the churches of apostolic times. However, because "the church has not yet half recovered," he wrote, the people of God were "scattered and divided" among the various Protestant sects. Consequently, Christians of the Restoration Movement, immersed as believers, were compelled "to recognize as Christians many who have been in error on baptism, but who in the spirit of obedience are Christians indeed. (See Rom. ii. 28, 29)."
Referring to the various sects who had taught much truth over many generations, Errett insisted that it would never do "to unchristianize those on whose shoulders we are standing, and because of whose labors we are enabled to see some truths more clearly than they." Therefore, in regard to the Lord's Supper, the standard practice was "neither to invite nor reject particular classes of persons, but to spread the table in the name of the Lord, for the Lord's people, and allow all to come who will, each on his own responsibility."
Errett reported his impression that "fully two-thirds of our churches in the United States occupy this position," with those churches that were originally Baptist being "rather more unyielding." He concluded with words of both conviction and generosity: "For myself, while fully devoted to our plea, I have no wish to limit and fetter my sympathies and affections to our own people."
For his part, Robert Richardson argued that because Christianity in apostolic times was not divided into organized sects, the question at hand, being "anterior to the apostacy," could not be discussed or decided on the basis of Scripture. In other words, because the first-century church was presumably united on all essentials, the New Testament did not contain an answer to the question of whether a church should permit unimmersed believers to participate in the Lord's Supper. Therefore, "we neither discuss nor determine this question. We simply leave it to each individual to determine for himself. It is really, as the brethren . . . say, an 'untaught question'."
Citing Paul's words in 1 Corinthians 11:28--"But let a man examine himself, and so let him eat . . . ,"--Richardson asserted that the practice he advocated was "precisely in the spirit of this injunction, and we very properly forbear to decide the question either way, and consequently neither invite nor prohibit."
Like Errett, Richardson noted that the Scotch Baptists "are especially rigid in regard to this matter." Yet, he could vouch for them as "generally faithful and pious brethren" and thus suggested that "great forbearance" should be extended to those congregations.
W. K. Pendleton
In his follow-up "Remarks" on the question, editor W. K. Pendleton expressed his doubt that "the subject is one likely to develop any very serious controversy among the brethren." He approved what he referred to as the "almost universal" custom in Stone-Campbell churches to deny any authority "to exclude from the Lord's supper any who, by their walk and conversation, and in their own hearts, approve themselves as the Lord's people." Pendleton called on his readers to remember that "we are laboring, not to introduce a totally new church, but to restore the things which are wanting in one already existing; not to overthrow what is good, buy to teach the way of the Lord more perfectly."
Pendleton concluded with a revealing flourish. In the following purple passage, there can be no doubt that the essential question was not "Who should partake?" The basic matter at stake was the question of who should be regarded as a believer?
If Peter had been left to his Jewish prejudices and exclusivism, he would doubtless have refused to admit Cornelius to baptism. It was the overwhelming evidence of his reception by God that compelled the apostle to say, 'Who shall forbid that he shall be baptized?' So ought it to be with us. Can we deny that God has recognized and is still recognizing the truly pious and full of faith and good works in the many divisions of professed Christians, as really and truly his people? Will any one take the absurd position that the noble list of illustrious men who have been the light and ornament of religion in the ages that are past, and whose piety and learning are still the admiration and glory of the Lord's people--that all these, because of an error, not on the significancy or divine authority of baptism, but what we must be allowed to call its mode,--that all these, because of such an error, must be pushed from our ranks as reprobate--torn from our Christian affections, as heretics--thrust from the communion of the body and blood of the Saviour, whom for a long life they so truly loved and devotedly served, and counted no more worthy of our Christian fellowship than so many heathens and publicans! The conclusion is too monstrous for any but the hide-bound zealot of a cold and lifeless formalism. I should feel that I had injured the Christianity which I profess and which I love, could I recall that even for a moment I had allowed by head so to interpret its pleading mercy, or my heart so to restrict its wide-embracing charity.Such a vigorous defense of a generous restorationism clearly indicates that second-generation leaders of the Stone-Campbell Movement had much more than the Lord's Supper to discuss. The essential nature of the restoration plea and the position of the movement in the larger world of Christendom was the real issue.
 The responses from Errett, Richardson, and Pendleton appeared under the title "Communion with the 'Sects'" in the The Millennial Harbinger dated December 1861, Vol. 32, 711-714. This material was reprinted in Benjamin Lyon Smith, The Millennial Harbinger Abridged, Vol. 2 (Cincinnati: Standard, 1902), 239 and following.
Lester G. McAllister and William E. Tucker, Journey in Faith: A History of the Christian Church (Disciples of Christ) (Saint Louis: Bethany Press, 1975), 237.
 The approximate birth and death dates for Richard Hawley are taken from McAllister and Tucker, Journey in Faith, 240. For Hawley as the ACMS representative from Michigan, see The Millennial Harbinger Abridged, Vol. 2, 400.
 McAllister and Tucker, Journey in Faith, 240.