But I said: “I have toiled for nothing. I used up my strength for an unreality, in vain. But surely my judgment is with Jehovah, And my wages with my God.”
Jesus Christ was perfect. He came to earth knowing what he must do and he would never doubt his ability (as an imperfect man would) to accomplish his commission. He would not be disheartened. Failure was not even a thought that would enter his mind. These are not the thoughts of God’s Son. They are the thoughts and feelings of an imperfect messenger who feels like his endless toil to educate and deliver his message is going unheard. Deep down though, this man knows that Jehovah has sent him and that he will succeed and be rewarded for his efforts.
Here is an interesting video Isaiah 49 | The End Time Prophet, the Coming Elijah on the topic: