I've started on a version of this post several times, but for some reason it never comes out right and either abandon it before posting or delete it soon after. I'm not sure why.
There's a joke that gets made in Rome, that Rome is the 'deposit of faith.' That is to say that one arrives in Rome with faith, or at least because of the faith, but that living and working in Rome causes one to lose the faith. Thus, when one leaves Rome, the faith is left behind, 'deposited' there.
One time the brothers were joking about this and one them said that this actually worked out for the benefit of someone in Rome who wanted to live devoutly and carefully, because there was a lot of unclaimed faith lying around that could be had. It could seem like a silly comment on the face of it, but it really stuck with me and I think it points to something very true.
After all, we believe that as the Universal Church we are a communion, and thus that the graces we have and enjoy in Christ are meant to be shared and held in common. Therefore we pray for each other here in the Church on pilgrimage in time and space, just as we ask the prayers of those who already find themselves as the Church in heaven. We offer thanksgiving to God for each other's faith and the blessings God has worked for the world through those we know, as we also make sacrifices on behalf of others. And it is all meant to be this way that the Church may be one precisely as a communion of saints.
After all, since grace is nothing else but the presence of God himself, I suppose that it can't just evaporate or be destroyed. So if someone loses the faith, it doesn't just go away. It's somewhere (in the spiritual sense), waiting perhaps, with the sublimely humble patience that only God himself has. I think about that when I run into 'reverts,' folks who drifted away or apostatized from the faith at some point, only to come back years later and usually much stronger. Where was their faith during the time they were away? On the one hand, it certainly never left them, the irrevocable grace of baptism dwelling in their souls the whole time, a sign of the Crucified Lord who blesses and saves even those who disregard him and do him violence. But perhaps their faith was also kept nourished and alive in the midst of the communion of saints which is the Church, kept and cherished by others until it rejoiced to be claimed anew.
I think about this sometimes when I meet someone, either on the internet or in real life, who has left the faith, either by drifting away or by apostasy. I pray to remember that it may be my responsibility to hold and keep safe the grace of that person's faith until, in God's time, he is ready to take it up again. And maybe I can be inspired by the hope that if I do it well, that person might one day become a 'revert' of great strength and devotion, with a faith more dynamic than any he knew before.
Maybe it's crazy or weird, but sometimes I make that my prayer as I do the little errands I have to do sometimes in Rome, taking the bus, walking by the offices that support the practice of the life of faith of all the Churches, that if anyone's faith has been deposited, abandoned, or left anywhere along the way, I might offer myself to God as one willing to carry and keep safe that faith until someone was ready himself to cherish it again.