Chapter 49: Messiah = Light unto the Gentiles
The servant speaks in his own voice – he has been called from the womb. His mouth has been made like a sharp sword. He will be a light to the gentiles. He will release prisoners, and those in darkness. The Lord cannot forget Israel, as a nurse cannot forget her nursing child. The Lord will protect Israel from her enemies, who will be humbled and defeated.
Chapter 50: Isaiah shall have a tongue of power
Israel has brought its misfortunes on itself. The servant is obedient, and has been given a wise tongue. “… the tongue of the learned, that I should know how to speak a word…” (Isaiah 50:4)
”I gave my back to those smitters, and my cheeks to them that plucked off the hair…” (Isaiah 50:6) He has faith that the Lord will justify him, however, and that his adversaries will grow old like a garment, and be eaten up by moths. People will be kindled by fire from his hand.