He said to me, “You are my servant,
    Israel, in whom I will display my splendour.”
4 But I said, “I have laboured in vain;
    I have spent my strength for nothing at all.
Yet what is due me is in the Lord’s hand,
    and my reward is with my God.”

In the early part of chapter 49 we can maybe see some parallels with Jeremiah (or with his experience) But I have found Barry Webb’s comments on this passage very helpful. Here they are:

‘Like Jeremiah…he meets with opposition which brings him close to despair – but carries on anyway, trusting God to reward him (4). But just as we are beginning to think he must be Jeremiah or some other known prophet, he is referred to in a way which explodes all our categories and puts him in a class of his own:

You are my servant,
    Israel, in whom I will display my splendour. (3).

His name is Israel! But how can this be, since, as we have already seen, a key aspect of his mission is to restore Israel to a proper relationship with God (5)? We are forced to look back to the tentative conclusion we reached in chapter 42, that he is a figure who embodies all that the nation of Israel was called to be, and therefore one who is truly worthy of the name – God’s perfect Servant. As such he is far greater than Jeremiah, or any other Old Testament prophet for that matter. He is the prophet par excellence.‘ (‘Isaiah’, pp.193/4).