Isaiah 8:19

And when they — The Israelites, who are fallen from God, into superstition and idolatry. You — My children, whom the prophet arms against the common temptation. Mutter — That speak with a low voice, as these two words signify, which they affected to do, speaking rather inwardly in their bellies, than audibly with their mouths. Should not — This answer the prophet puts into their mouths, doth not every nation, in cases of difficulty, seek to their gods? Much more should we do so, that have the only true God for our God. For the living — That is, for living men to enquire of the living God, is proper and reasonable; but it is highly absurd for them to forsake him, and to seek dead idols, either to the images, or to the spirits of dead men, which are supposed to speak in them.