"Some rejoice and exult that they have the gifts, which others have not. May God deliver His people from such gifts. What do these gifts do for them? Are they through the exercise of these gifts, brought into the unity of the faith? And do they convince the unbeliever that God is with them of a truth? When these discordant ones, holding their different views, come together and there is considerable excitement and the unknown tongue, they let their light so shine that unbelievers would say: These people are not sane; they are carried away with a false excitement, and we know that they do not have the truth. Such stand directly in the way of sinners; their influence is effectual to keep others from accepting the Sabbath. Such will be rewarded according to their works. Would to God they would be reformed or give up the Sabbath! They would not then stand in the way of unbelievers. 1T 418.2"
"If therefore the whole church be come together into one place, and all speak with tongues, and there come in those that are unlearned, or unbelievers, will they not say that ye are mad?"
Both passages discuss the negative impression that speaking in tongues can have on unbelievers, leading them to think the believers are mad.