Psalms 137:6
If I do not remember thee, let my tongue cleave to the roof of my mouth; if I prefer not Jerusalem above my chief joy. If I do not remember thee, let my tongue cleave to the roof of my mouth; if I prefer not Jerusalem above my chief joy.
The verse is a vow to accept the silencing of the tongue rather than use it against what is sacred. Its spirit prefers loss of speech to speech that dishonors holy things. Applied to councils and assemblies, when words spoken there oppose the principles of God's Word, remaining silent would be better than speaking.