For my thoughts are not your thoughts— This whole period consists of two comparative sentences; the one of which sets forth the height and sublimity of the thoughts and ways of God, above the thoughts and ways of men; the other, the undoubted power of the word of God, sent forth by him to effect the salvation of mankind. The former is grounded upon the perfect knowledge of God; the other, upon his infinite power. This passage is well connected with the whole argument of this and the former section, as well as with what immediately precedes, respecting the calling of the Gentiles. Concerning the metaphor in the 10th verse, it should be observed, that the word of God, especially his prophetic word, is usually compared in Scripture to rain. See Deuteronomy 32:2. Job 29:22-23. When the inspired writers, therefore, intend to describe the certain completion of any prophesies, they represent it frequently under the image of rain, which impregnates and fertilizes the earth. Isaiah, having in the long prophesy from chap. 40: and especially in Isaiah 55:3-5, of this chapter, displayed the covenant of God with the Israelites, and the due performances of his mercy towards David, established by an oath, wherein he promised that there should never be wanting a king to sit on his throne, and that the person peculiarly designed for this high office, should be teacher and king of the Gentiles; in order to convince any one who should think this incredible, he bids them consider, that the ways of God are immensely higher than those of men; and that those things are easy to him, which are difficult to us. He adds, that the completion of the prophesies, however wonderful, would be inevitably certain; that the prophetic word of God was like unto snow or rain, which, as they do not return to heaven till they have answered the end in watering, impregnating, and fertilizing; in giving bread to the hungry, and seed to the sower; so likewise the prophetic word would accomplish its end, that is to say, its predictions. See Michaelis and Vitringa.
Related Commentaries of Isaiah 55:8
Isaiah 55:8-11
8 For my thoughts are not your thoughts, neither are your ways my ways, saith the LORD.
9 For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts.
10 For as the rain cometh down, and the snow from heaven, and returneth not thither, but watereth the earth, and maketh it bring forth and bud, that it may give seed to the sower, and bread to the eater:
11 So shall my word be that goeth forth out of my mouth: it shall not return unto me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it.