The apostle Paul makes the best comment upon this, when he applies it to the sovereignty of grace: Romans 9:17.
Related Commentaries of Exodus 9:15
Exodus 9:15-16
15 For now I will stretch out my hand, that I may smite thee and thy people with pestilence; and thou shalt be cut off from the earth.
16 And in very deed for this cause have I raised thee up, for to shew in thee my power; and that my name may be declared throughout all the earth.