Isn't that kind of begging the question? You have to prove that its not within the abilities of the fallen nature to respond to God's appeal for man to be reconciled from that fall. To do that you have to either establish:
1. That God's appeal is just too weak in nature to enable the fallen man to respond.
or
2. That man's fallen nature is just too strong for God's appeal to have an enabling effect.
Good luck.
Christians do not believe in good luck. We believe in the good Lord.
There is another possibility which you have not considered.
It is that which is stated quite clearly in God’s Word:
God humbled himself to become man to accomplish that which Adam and all his progeny could not and would not do…..obey God perfectly.
Through His obedience men could now be justified by faith in the perfect work and person of Christ.
Though Christ committed no sin, doing nothing less than holy works perfectly pleasing to God, men hated Him to such an extent that they nailed Him to a cross.
The fault was not in God, who did not and cannot sin.
The fault lay in men, who could only sin.
But despite their hatred, Christ died for the ungodly.
The Bible calls those for whom Christ died ‘the Elect.’
The Elect are the Chosen…….chosen for salvation.
God the Father did the choosing….before the Elect were born…..before they had done anything good to deserve God’s favor.
He personally selected them out of the mass of sinful humanity.
It was His choice to be merciful to them.
He did not have to be merciful to anyone.
He freely, willingly chose to do so.
God's will is truly free.
Those He elected to salvation will infallibly be saved for all eternity.
God says so.
God cannot lie.
God can guarantee the salvation of the Elect because the salvation of the Elect is all of God’s effective work which will infallibly accomplish that very purpose.
And God cannot fail to accomplish His purpose in any work He does.
Otherwise He would not be God.
Does God require faith in Christ?
God gives the Elect the faith necessary to believe unto salvation.
In fact, He graciously gives the Elect all the gifts necessary to salvation.
This is why we say, 'salvation is of the Lord.'
That, in summation, is how men are saved.
Those sinful men whom the Lord does not choose for salvation are passed by.
No injustice was done by passing them by.
Grace is owed no man.
Justice is owed every man.
Justice owed the Elect was satisfied in Christ's substitutionary death.
Justice owed the Reprobate will never be fully satisfied by their eternal punishment.
Is not God too wonderful for words and worthy of our heartfelt worship?