In the previous chapter, Isaiah brought a message of comfort in which he says to God’s People “Here is your God!” (40:9). This chapter begins and ends with a challenge to the nations to wake up to who God is. Who is the true ruler of the world? is the question – who controls all that happens in the present (vv.1-7) and is able to predict all that will happen in the future (vv.21-29)? In the face of all the turbulent events in the world, where do the nations look for strength? – there’s an invitation in v.1 to know the same renewal of strength promised to God’s People in 40:31, but vv.5-7 describe how the nations look to their own strength and the pathetic idols of their own making. Then in vv.21-29 they are asked where they look for guidance, and again the pathetic inadequacy of their idols is exposed.
But the heart of the chapter (vv.8-20) is a word of encouragement to God’s own people. The challenge addressed to the nations was as much a word to His people to encourage them to trust in Him. His commitment to them and His grace to them is wonderfully made plain. Motyer summarizes neatly –
The present passage [ie vv.8-20] brings … three pictures assuring of divine intervention: human hostility (8-13, the servant whose enemies are vanquished); personal weakness (14-16, the worm which becomes a threshing sledge); and adverse circumstances (17-20, the desert traveller miraculously provided for).
They are weak, but God is their Helper, who will protect them, use them in their weakness, and provide for them in their need. So they are not to fear (vv.10,13), but to trust Him. In the background still we might remember their complaint in 40:27. All this is an encouragement to us too, obviously.