"The principle presented by Paul concerning the gift of tongues, is equally applicable to the use of the voice in prayer and social meeting. We would not have any one of you who is defective in this respect, cease from offering public prayer, or from bearing witness to the power and love of Christ. I do not write these words to silence you; for there has been already too much silence in our meetings; but I write that you may consecrate your voice to Him who gave you this gift, and realize the necessity of cultivating it so that you may edify the church by what you say. If you have acquired the habit of speaking in a low, indistinct way, you should regard it as a defect, and put forth earnest effort to overcome, that you may honor God and edify his children. CE 130.1"
"But he that prophesieth speaketh unto men to edification, and exhortation, and comfort."
The EGW passage directly applies the principle of edification from 1 Corinthians 14:3 to the use of voice in prayer and testimony, emphasizing the importance of clear and edifying communication within the church.