I, even I; both the foreknowledge and the execution of this great achievement cannot be ascribed to idols, but to me only. He shall make his way prosperous; God will give him good success in this undertaking. Here is a sudden change of the person from I to he, which is very usual. Or, as others render it, he shall prosper in his way; the preposition in being most frequently understood.
Related Commentaries of Isaiah 48:15
Isaiah 48:15
15 I, even I, have spoken; yea, I have called him: I have brought him, and he shall make his way prosperous.