Romans 9:20

Nay but, O man, who art thou that repliest against God? Shall the thing formed say to him that formed it, Why didst thou make me thus?

Man has no right to arraign God in his thoughts and to charge him with unrighteousness and dispute his decisions. Even if, by the feeble lamp of human knowledge, no adequate reason appears as to "why" God did certain things, the creature is in no sense a judge of the Creator. The most fundamental of all considerations relative to God is that God is altogether righteous, holy, and good; and that, whatever of his decisions may appear to people as otherwise, the fact of their righteousness and justice remains unimpaired. It was a part of the honor of Abraham that he had such a conviction of God's righteousness. In that patriarch's great intercessory prayer for Sodom, he prayed, "Shall not the judge of all the earth do right?" (Genesis 18:25). Abraham's prayer was founded in the deepest of inner convictions that God is good and righteous.

Jesus himself expounded this same principle in the parable of the talents, wherein the one-talent man viewed God (his lord in the parable) as "a hard man" (Matthew 25:24). God's response to that accusation was the expulsion of the wicked and slothful servant. In the same manner here, Paul did not argue the point but cited the wickedness of the heart which will raise such a question, such a questioner being clearly one who interposes his own will as antithetical to that of God, vainly supposing that finite intelligence is capable of judging the actions of God. The evil judgment uttered by the one-talent man in the parable was the child of his own wicked heart and not due to any wrong doing on the part of his Lord. Paul taught here that any allegation to the effect that God would condemn a sinner that God had hardened himself can originate in none other than a wicked heart.