Luke 12:47-48 (see also John 9:39-41; Romans 2:1-16)
“And that slave who knew his master’s will and did not get ready or act in accord with his will, will receive many lashes, but the one who did not know it, and committed deeds worthy of a flogging, will receive but few. From everyone who has been given much, much will be required; and to whom they entrusted much, of him they will ask all the more.”
According to the Calvinist doctrine of Total Inability, simply knowing God’s Will makes no difference, since one is totally unable to do it, apart from an Irresistible Grace.
In this parable, you can see the Lord’s principles of justice. Consider other examples:
Luke 23:34: “But Jesus was saying, ‘Father, forgive them; for they do not know what they are doing.’ And they cast lots, dividing up His garments among themselves.”
In this case, they were ignorant, and though they deserved condemnation for what they did, the Lord’s principles of justice prompted Him to beg His Father for their forgiveness, so that their crime against Him would not be imputed to them. What’s interesting is when you extrapolate this principle. This reveals God’s character to be infinitely fair-minded.
John 9:39-41: “Jesus said, ‘For judgment I came into this world, so that those who do not see may see, and that those who see may become blind.’ Those of the Pharisees who were with Him heard these things and said to Him, ‘We are not blind too, are we?’ Jesus said to them, ‘If you were blind, you would have no sin; but since you say, “We see,” your sin remains.’”
In other words, if they were blind, they would not have the penalty of their sin imputed to them. But since they admit that they see, the penalty of their sin will indeed be imputed to them.
John 15:22: “If I had not come and spoken to them, they would not have sin, but now they have no excuse for their sin.”
This reveals God’s standard of justice. Knowing that Jesus is the Judge (John 5:22-23), it stands to reason that He will judge in this manner, understanding that some people have somewhat of an excuse, and the proportion of guilt will be applied accordingly, as shown at Luke 12:48.
John Calvin writes: “When God prefers some to others, choosing some and passing others by, the difference does not depend on human dignity or indignity. It is therefore wrong to say that the reprobate are worthy of eternal destruction.” (Concerning the Eternal Predestination of God, pp.120-121, emphasis mine)
Calvin adds: “If what I teach is true, that those who perish are destined to death by the eternal good pleasure of God though the reason does not appear, then they are not found but made worthy of destruction.” (Concerning the Eternal Predestination of God, p.121, emphasis mine)
Bringing it all together, if someone was created and predestined to commit a certain sin, fixed by an eternal decree, then that would be their “excuse.” If all was decreed, as per Calvinism, then every sin would have an excuse, and it would undermine divine justice altogether. Now a Calvinist may respond with the typical, “Who are you O man to judge God,” but the point is that God Himself is the One who established these principles of justice, outlined in the aforementioned verses. Who better than God, would know that an immutable decree would be a legitimate excuse? Calvinism would totally destroy the principles of divine justice.
For more on this point, see here. In other words, additional grace is contingent upon the response to the grace given. When someone spurns God, they stand to receive His wrath (rather than blessings), which has a cascading effect upon others. The reverse is also true. When someone receives God, they stand to receive more blessings. This is illustrated at Jeremiah 18:1-13.