John Calvin Commentary Isaiah 66:9

"Shall I bring to the birth, and not cause to bring forth? saith Jehovah: shall I that cause to bring forth shut [the womb]? saith thy God." — Isaiah 66:9 (ASV)

Do I bring to the birth? As in the preceding verse he extolled in lofty terms the work of God, so he now shows that it should not be thought incredible, and that we should not doubt His power, which surpasses all the order of nature; for, if we consider who it is that speaks, and how easy it is for Him to perform what He has promised, we will not remain in such uncertainty as not to instantly recollect that the renewal of the world is in the hand of Him who would have no difficulty in creating a hundred worlds in a moment.

A little before, by a burst of astonishment, he intended to magnify the greatness of the work. But now, lest the minds of good people should be perplexed or embarrassed, he exhorts them to consider His strength; and, in order that he may more fully convince them that nothing is so difficult in the eyes of people as not to be in His power and easily performed by Him, he brings forward those things which we see every day; for in a woman’s bringing forth a child we see clearly His wonderful power.

Will not the Lord manifest Himself to be far more wonderful in enlarging and multiplying the Church, which is the principal theater of His glory? It is therefore exceedingly wicked to limit His strength, by believing that He is less powerful when He chooses to act directly and by openly stretching out His hand, than when He acts by natural means.