Jerome : "Consider the work of God: for who can make that straight, which he has made crooked? "Symmachus translates this passage in this way: "learn the word of God, because no one can correct what He has ruined". That is he supplies from the Holy Scriptures, or from thinking of the elements, to know and understand those things, which are done; but not to ask the causes and reasons why one thing is done in this way, or why it ought to have been done differently from the way in which it has been done. For the sake of this passage, if anyone should ask why God spoke to Moses in this way: "who makes the dumb and the deaf, the seeing and the blind, am I not the Lord God?" [Ex. 4, 11.], and if he should say, why are the blind, the deaf, the mute created in this way, and others similar to these? This passage must be seen in reference to Psalms 17, in which it is said to the Lord: "You will be Holy with the holy man, and with the wicked You will err" [Ps. 17, 26-27.]. And it must be added that the Holy Lord is with him, who is holy; and the wicked are with him, who was previously wicked by his own will. This is similar also to that which is written in Leviticus: "if the wicked came to me I will go to them, wicked in my madness". [Lev. 26-27.] Even this can explain why God hardened the heart of Pharaoh. For just as one and the same quality of the sun melts wax and dries clay, and on account of each one's constitution, both wax melts and clay dries; [Cfr. Lucr. De Rerum Natura VI 962/965; Verg. Ecl. VIII 80.; Hier. Epist. 120,10 -12. CSEL 55, p504,10.] so too the one quality of the portents of God in Egypt softened the heart of those who believed, and hardened that of the incredulous, who just as their hardness and impatient heart, began to store up for themselves anger for the day of anger from those portents, which they didn't believe, though yet they saw them happen. — Commentary on Ecclesiastes