'Mouth of the Lord' in the Bible

“But if you refuse and rebel,You will be devoured by the sword.”Truly, the mouth of the Lord has spoken.

Then the glory of the Lord will be revealed,And all flesh will see it together;For the mouth of the Lord has spoken.”

Then you will take delight in the Lord,And I will make you ride on the heights of the earth;And I will feed you with the heritage of Jacob your father,For the mouth of the Lord has spoken.”

The nations will see your righteousness,And all kings your glory;And you will be called by a new nameWhich the mouth of the Lord will designate.