"Can a ... leopard change his spots? Neither can you do good who are accustomed to doing evil.
" - Jeremiah 13:23
There are a number of professing Christians who have actually been taught that God would never require us to do anything we are incapable of doing. But does not the whole Bible teach that we are required to obey the Law? Yet not one person, save Jesus, can perfectly obey the law? In fact, Paul declares that the purpose of the Divine legislation was not to show our moral ability, but to reveal sin i.e.. our utter inability and impotence to obey the law (see Rom 3:19, 20). Further, there was nothing that obligated God to send His Son to redeem us. He could have justly required the fallen human race to obey the Law and left us to ourselves to try ... and then He could have swept us all away in judgment when each of us failed to do so.
That people are accountable to do things they are incapable of doing is also evident in every day life. Consider those who borrow large sums of money from the bank and then lose it all through some foolish act. Their inability to repay the bank in no way alleviates them from the responsibility to do so. If the Arminian makes the charge that inability alleviates responsibility, then it follows that once I squandered the money away then I am no longer responsible to repay it. That I am off the hook. But we all know this is not the case. Likewise, in Adam, we all owe a sin-debt that we cannot repay. The Arminian reasons that we are therefore no longer responsible for it if we can do nothing about it.
But, thanks be to God, that in the gospel, Jesus does FOR US what we are unable to do for ourselves. He pays our debt in full. He is not required to save us but, in His great mercy, out of the mass of ill-deserving sinners, He redeems a people for Himself, a number that no man can count. Some wrongly teach that it is the man who exercises his free will who is saved but the Bible teaches (and I quote) "it is not the man who wills or runs, but God who has mercy." (Rom 9:16)
Human Inability by C H Spurgeon
Responsibility, Inability, Monergistic Grace (chart)
Man's Utter Inability to Rescue Himself by Thomas Boston
Inability by A.A. Hodge
The Myth of Free Will by Walter Chantry