'Mouths' in the Bible

So He will sprinkle many nations [with His blood, providing salvation],Kings will shut their mouths because of Him;For what they had not been told they will see,And what they had not heard they will understand.

“As for Me, this is My covenant with them,” says the Lord: “My Spirit which is upon you [writing the law of God on the heart], and My words which I have put in your mouth shall not depart from your mouth, nor from the mouths of your [true, spiritual] children, nor from the mouth of your children’s children,” says the Lord, “from now and forever.”