'Mouth' in the Bible

Now we know that whatever the Law says applies to those who are under the Law, so that every mouth may be silenced and the whole world held accountable to God.

But what does it say? "The message is near you. It is in your mouth and in your heart." This is the message about faith that we are proclaiming:

If you declare with your mouth that Jesus is Lord, and believe in your heart that God raised him from the dead, you will be saved.

For one believes with his heart and is justified, and declares with his mouth and is saved.