'Mouth of the Lord' in the Bible

And he cried unto the man of God that came from Judah, saying, Thus saith the LORD, Forasmuch as thou hast disobeyed the mouth of the LORD, and hast not kept the commandment which the LORD thy God commanded thee,

And when the prophet that brought him back again from the way, heard thereof, he said, "It is the man of God which disobeyed the mouth of the LORD. And therefore the LORD hath delivered him unto the lion which hath rent him and slain him, according to the word of the LORD, which he said to him."