Isaiah 51:12 in the King James Version
I, even I, am he that comforteth you: who art thou, that thou shouldest be afraid of a man that shall die, and of the son of man which shall be made as grass;
Context
11 Those ransomed by the LORD will return, and come with singing to Zion. Everlasting joy shall be on their heads. They will obtain gladness and joy. Sorrow and sighing shall flee away.
12 “I, even I, am he who comforts you. Who are you, that you are afraid of man who shall die, and of the son of man who will be made as grass?
13 Have you forgotten the LORD your Maker, who stretched out the heavens, and laid the foundations of the earth? Do you live in fear continually all day because of the fury of the oppressor, when he prepares to destroy? Where is the fury of the oppressor?