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;
I, (even) I, (am) he that comforteth you - (Isaiah 51:3; Isaiah 40:1.)
Who (art) thou - Zion.
That thou shouldest be afraid of ... the son of man - frail and dying as his parent Adam.
(Which) shall be made as grass - shall wither as grass (Isaiah 40:6-7).