At 20:00 - 21:30 in his testimony, Mr. Geoffrey Jackson - in answer to Mr. Stewart's question about the governing body claiming to be God's spokespersons - claimed that it would be presumptuous of them to say that they were the only spokespersons which God was using.
Mr. Jackson doesn't seem to know what he and his fellow G.B. members - and the providers of his lifestyle, the WTBTS - actually teach as "Bible truth." Some people might even say he lied to the Royal Commission, in view of the evidence!
w09 11/15 p. 14 par. 5 Treasure Your Place in the Congregation - By word or action, may we never challenge the channel of communication that Jehovah is using today. (Num. 16:1-3) On the contrary, we should cherish our privilege to cooperate with the slave class. And should we not strive to be obedient and submissive to those taking the lead in our local congregation?
w06 7/15 p. 22 par. 16 Focus on the Goodness of Jehovah’s Organization - The ‘faithful slave’ may eventually publish something that answers our questions and clears up our doubts. It is wise to seek the help of Christian elders. (Jude 22,23) Prayer, personal study, and association with spiritually-minded fellow believers can also help to remove doubts and can deepen our appreciation for the faith-strengthening Bible truths we have learned through Jehovah’s channel of communication.
w06 10/15 p. 7 Taking in Knowledge of God—How? - Where can we find assistance in understanding the Word of truth and then in living in accord with it?.... Christ.....does so through his trusted and loyal followers, who make up the channel responsible for directing and protecting earnest seekers of truth. (Matthew 24:45-47
w03 3/15 p. 27 ‘The Lips of Truth Will Endure Forever’ - Jehovah gives us sound counsel through his Word and through his organization, using the publications provided by "the faithful and discreet slave." (Matthew 24:45) We "must be swift about hearing" when Jehovah, "the One teaching men knowledge," counsels us through his channel of communication.
w94 10/1 p. 8 The Bible—A Book Meant to Be Understood - JESUS assured us that after his death and resurrection, he would raise up a "faithful and discreet slave" that would serve as his channel of communication. (Matthew 24:45-47) All who want to understand the Bible should appreciate that the "greatly diversified wisdom of God" can become known only through Jehovah’s channel of communication, the faithful and discreet slave.
w92 11/15 pp. 19-20 par. 7 Serve Jehovah Loyally - Years ago a few elders lacked such appreciation. One observer noted that these men "were critical of the articles in The Watchtower, not wanting to accept it as God’s channel of truth, always trying to influence others in their way of thinking." However, loyal elders never try to influence others to reject any of the spiritual food provided by God through the faithful slave.
w91 9/1 pp. 18-19 par. 15 Jehovah and Christ—Foremost Communicators - As foretold at Matthew 24:3, 45-47, the Master, Jesus Christ, has appointed "the faithful and discreet slave," made up of anointed Christians, to care for all his belongings on earth during this day of his presence. That faithful and discreet slave is represented today by the Governing Body of Jehovah’s Witnesses, which has as its publicity agent the Watch Tower Bible and Tract Society. Most appropriately, that faithful and discreet slave has also been called God’s channel of communication.
w90 10/1 p. 30 Do You Follow Instructions? - We should follow the instructions that the Head of the Christian congregation, Jesus Christ, gives through "the faithful and discreet slave," the appointed channel of God’s organization here on earth. (Matthew 24:45-47
w81 12/1 pp. 27-28 pars. 4-6 The Path of the Righteous Does Keep Getting Brighter - Unless we are in touch with this channel of communication that God is using, we will not progress along the road to life, no matter how much Bible reading we do.—Compare Acts 8:30-40. 5 Regarding God’s channel of communication, Jesus said that the "faithful and discreet slave" would provide spiritual nourishment at the right time for all his followers and that he would set this "slave" over all his belongings. (Matt. 24:45-47) 6 This "faithful and discreet slave," which is associated with Jehovah’s Witnesses, has indeed been used by Jehovah God to guide, strengthen and direct his people.
w67 8/1 p. 469 par. 20 Finding Contentment with Jehovah’s Organization - At times we hear brothers talking complainingly about the Scriptural explanations and truths published in The Watchtower. Being unable to understand fully why a certain point is made or why a clearer understanding of a particular point has been given, they begin expressing their doubts to others. This, of course, creates confusion among the brothers, especially among the newer ones, and it certainly does not help the complainer in any way. He is showing a spirit of discontent with Jehovah’s channel of communication, in many cases doing so hastily and prematurely without a full knowledge of all the facts involved.
w66 1/15 p. 44 par. 10 The Value of Right Association Through Congregational Meetings - Today the anointed spirit-begotten witnesses of Jehovah, comprising the "faithful and discreet slave," serve as an earthly channel of communication for the great crowd of people who will survive Armageddon. These anointed witnesses along with the "great crowd" of companions form the modern-day Christian organization through which God’s spirit is in operation. (Matt. 24:45-51; Rev. 7:9-17) Never has God had more than one channel of communication at one time. Failure to recognize and associate with his anointed witnesses would certainly indicate that one is not in Jehovah God’s organization and under his spirit.
I'm sure Mr. Stewart was well aware of what the literature says - despite Mr. Jackson's "humble" answer!