Q. 9. Doth not God then do injustice to man, by requiring from him in His law, that which he cannot perform?
Not at all; for God made man capable of performing it;  but man, by the instigation of the devil, and his own wilful disobedience, deprived himself and all his posterity of those divine gifts.
 Ecclesiastes 7:29;  John 8:44; 2 Corinthians 11:3;  Genesis 3:4, 7;  Romans 5:12.
Q. 10. Will God suffer such disobedience and rebellion to go unpunished?
By no means; but is terribly displeased with our original as well as actual sins; and will punish them in His just judgment temporally and eternally, as He hath declared, “Cursed is every one that continueth not in all things, which are written in the book of the law, to do them.”
 Psalm 5:5;  Romans 1:18; Deuteronomy 28:15; Hebrews 9:27;  Deuteronomy 27:26; Galatians 3:10.
Q. 11. Is not God then also merciful?
God is indeed merciful, but also just; therefore His justice requires, that sin which is committed against the most high majesty of God, be also punished with extreme, that is, with everlasting punishment of body and soul.
 Exodus 34:6;  Exodus 20:5; Job 34:10–11;  Psalm 5:5–6;  Genesis 2:17; Romans 6:23.
In the last two Lord’s Days we learn that fallen man is unable to keep God’s law perfectly, but God requires man to keep the law perfectly on the pains of eternal death. But this is impossible and it does seem that God is unfair in His requirement, just as it would be unfair and unjust for a mother to penalise her 2-year-old for being unable to read! But is God unjust? Obviously not! God is not unjust because He had made man capable of obeying Him perfectly; but Adam our representative father, under the temptation of Satan and his own wilful disobedience, fell into sin and so deprived himself of that ability to keep the commandments of God perfectly. And since he is, by nature and divine appointment, our federal representative, he forfeited the divine gifts necessary for perfect obedience for us too. Let me give a loose illustration. Suppose you are a citizen of country X, which has an elected president. Suppose when the nation first gained independency, the World Bank gave a loan of $100 billion to the president as the head of state, to start up the economy, on condition that each citizen pays an interest to the bank every year. The president is supposed to distribute the amount to every citizen in the nation in order that all may start up their businesses. But instead of doing so, he squandered the whole amount away in big-time gambling. Presently the president died, and the citizens discovered themselves to be debtors. Now, would it be right for the citizens of the city to sue the World Bank for unfairly withholding funds from them and requiring that they pay the yearly tax? Obviously not. Would it be wrong for the World Bank to sue the citizens of the city in order to recover the losses, seeing it was their president who wasted the money away? Obviously not. So it is the case that God is not unfair to require all men to keep His laws perfectly.
Heidelberg Catechism >