Your soul shall live... — Better, revive. The idea is that of waking to a new life.
I will make an everlasting covenant... — The words find their explanation in the “new covenant” of Jeremiah 31:31; Luke 22:20, but those which follow show that it is thought of as the expansion and completion of that which had been made with David (2 Samuel 7:12-17; Psalms 89:34-35), as the representative of the true King, whom Isaiah now contemplates as identical with the “servant of the Lord.” For “sure mercies” read the unfailing loving-kindnesses, which were “of David,” as given to him and to his seed by Jehovah.