Free will means that there are souls who will be lost. They reject God, just as Satan did.
In one of my Facebook threads, someone made the following comment:
I don't like hell. I don't like when Mary said to the children at Fatima that people are going there because they have no one to pray for them. It really bothers me. The thought is awful. If it is true that someone should go to hell because I didn't pray for them then why should I go to heaven, having let so many perish so miserably when all they needed was my prayer? Lord please have mercy on a soul destined to be damned tonight because of my failure to pray. Have mercy on every soul that would die tonight. Your mercy is boundless. I beg you in the name of your Son's death to have mercy on every human that will die tonight. Forgive them for they didn't know what they were doing.
Everyone who goes to hell has had every chance to repent. God gives grace enough to all for them to repent, but some (many, apparently) choose not to. It's their fault in the end. Prayer and penance and love assuredly help them along the road, but ultimately each individual decides and each is accountable before God for their actions and beliefs:
Romans 14:10, 12 (RSV) . . . we shall all stand before the judgment seat of God; . . . each of us shall give account of himself to God.”
God's grace is sufficient to save them. But, sadly and tragically, they choose not to avail themselves of it.
I think we must simultaneously accept the following two truths:
1. It's always better to be the recipient of more intercessory prayer (and/or love or penance, etc.) rather than less.
2. Each individual is ultimately responsible for the fate of his or her own soul.
Much of Catholic thought, I've found, involves this “both/and” consideration. Things exist together in complementarity (though some are mysterious and paradoxical), that are often wrongly thought to be opposed to each other.
It would be like a scenario in which a husband or wife abandoned their spouse. We could say, “if only the forsaken one had been more loving or did more acts of kindness [or mutual friends had positively intervened more], maybe the other wouldn't have left.” Maybe so. That can always be said, can't it? Yet the person is still responsible for leaving and bears the primary blame.
The Blessed Virgin Mary wants to communicate to us (without doubt) that it's always good and crucial that we pray for souls. We have to love them and be compassionate and merciful; to evangelize and share! Prayer and other spiritual aids help people to repent and be saved, and they do so because God wants to include us in the process of others' redemption. Salvation is “social."
But each (ultimately damned) personalreadyhas enough grace to be saved from the outset and has chosen not to receive it. They ultimately have only themselves to blame if they are condemned to [i.e., choose] hell in the end. If they want to point to others and say, “They didn't do a, b, c, so I could be saved,” that becomes mere blame-shifting on their part. God can always reply by saying, “That's no excuse for you. I sent you x, y, and z, and situations 1, 2, 3 where you had more than ample opportunity to receive My grace and repent, but you steadfastly refused . . .”
Jesus noted (Lk 16:30-31) that even if a person is raised from the dead as a witness, folks who have already rejected the biblical message will still refuse to believe. If even the greatest miracles can't break through cases of such profound unbelief and rebellion, our prayers likely won't be able to, either. They've hardened their hearts.
The reprobate can always attempt to blame others, and God can always reply as above: that His grace was more than sufficient in each case, but was spurned and rejected. We will all stand accountable for our actions and our lives, regardless of what others did or didn't do. We've all fallen short and rebelled against God, and all must rely wholly on His free offer of grace, made possible by our Lord and Savior Jesus' death on the cross, to be saved in the end.
We should always pray for others, and we can always pray for any given person more than we do. Here the distinction between sufficient and efficient grace comes into play. Every soul is provided sufficient grace by God. But the reprobate spurn it. Prayer can help make the sufficient grace become efficient, so that they actually repent. But this is not automatic. Free will means that there are souls who will be lost. They reject God, just as Satan did.
After all, Satan himself was with God. He had everything any being could conceivably want: except that he wasn't God, and he couldn't handle that. He managed to rebel in heaven, while with God! No being could have any more “spiritual advantage” than that. But it wasn't efficient, to prevent his fall.
Free will means that the grace can always be rejected, and also intrinsically that it involves and involves the individual's own choice. That's why Calvinism, in order to bolster its double predestination, had to deny human free will and assert irresistible grace. The Catholic position is the contrary on both counts (though we do believe that God predestines the elect, while not eliminating their free will).
I don't believe, then, that we are responsible in some profound or direct way for a soul going to hell because we didn't pray hard enough for them, though we can always do more in any situation.
If we don't do our “duty” towards any given person, God in His mercy will surely send someone else or some other situation, to give the person every chance to repent and make it to heaven.