The Church can be divided into three parts: the Church Militant on Earth, the Church Triumphant in Heaven, and the Church Suffering in Purgatory. All parts of the Church are ceaselessly praying for each other, and it is through this prayer that God has chosen to place the vitality of the Church.
Through the saving power of Jesus Christ, death has been turned from a curse into a blessing. It is important to emphasize that this is indeed a blessing and not simply a lack of curse. In Christ, we will have communion with all others who are in Christ. We must therefore pray for our brethren and pray for those who are in Purgatory. Never fear to pray for a lost cause, as no prayer is ever wasted. Likewise, we must share the gifts that God has given us one with another, for what charity we give benefits the whole Church, and what sin we commit harms the whole Church.
The majority of the church fathers are of the opinion that more people, indeed more people claiming to be Christian, will be damned than saved. There is a minority who hold an opposing opinion. As overly-optimistic visions of Hell are not particularly helpful, so too are hellfire speeches which luridly describe the punishments of Hell are not useful. Prayer, however, is never wasted.
There was a theory expounded by Origen, among others, that all would be saved, in some theories extending even to the Devil. While the Church has never officially ruled out the more moderate versions of this theory, the clear language of the Bible is very difficult to square with this belief.
Still, we do not know what God knows, and there is no reason not to pray that we might have hope for salvation for any particular soul, or for souls in general.
Hell is not a pleasant subject, and some religions try to explain it away or ignore it entirely. How could a loving God commit any of his creation to unquenchable fire? The answer is that we choose it ourselves.
The damned have physical bodies, because the body helped commit the sins that damned the soul, so should the body participate in the punishment. Thus, we must take care to instruct our bodies to be virtuous, not corrupted by sin.
God cannot be seen as He is unless He allows Himself to be seen, which is termed the beatific vision. This is an unapproachable light (1 Tim 6:16), but we expect to see face to face in Heaven (1 Cor 13:12, Ps 17:15).
The Catechism also tells us that we will reign in heaven, though obviously not over God, and this implies that Heaven is not a static place. Rev 22, even taken literally, tells us that Heaven will be an immense place, a place that cannot be on Earth as it is, and Rev 21 tells us that it will be a new place with no more sadness. Paul, in Rom 8, tells us that we are groaning to be part of this new creation. Jesus tells us that we must lay up treasure in Heaven. We also know that there will be gender in Heaven, as we are repeatedly told that there will be people of both specific sexes there.
Despite the physicality of Heaven, we cannot expect carnality or a fleshliness there. 1 Cor 13:12 tells us that we will be face to face with God, and there cannot be any attachment to anything else when we are. Rev 22 tells us that we will have His name inscribed on our foreheads, such will be the communion with the Trinity in Heaven.
Section 1024f of the Catechism tells us that there will be many in Heaven, but it will not be to lose our identity to a corporate body. This does not means that there is no corporate body of the Church Triumphant, as Heaven is the community of all who are perfectly united in Christ, and Jn 15 speaks of us all as branches of Him, the true vine.
Benedict XII tells us that those who have died and have been purified or are not in need of purification are in Heaven, even before the resurrection. This is a place of surpassing beauty and where we will be in a union of love with God without any mediation.
We must still be resurrected on the last day, since we were created to be a union of body and spirit, but Heaven is still a timeless part of our progress into our eternal reward. We know that there is some bodily component to Heaven, as some there, such as Moses and Mary, were assumed bodily into Heaven. The body there, however, will be different from our bodies here.
Rev 21:27 says that nothing unclean shall enter Heaven, which is why it is necessary that there be a place where we are purified before we enter Heaven. 2 Maccabees explains that there must be a place, as there would be no sense in offering prayers for the dead otherwise. The Catechism, in section 1030ff, explains much about the doctrine of Purgatory. In Matt 12:31f, Jesus states that some things may be forgiven in the age to come, again providing evidence of forgiveness in the next life. Again, in Matt 5:23-26 and 18:18-35, Jesus tells us that we will never get out of our debt of sin until we have paid the last penny, implying that this place is not Hell, which no one will ever leave.
Aquinas tells us that the purgatorial fire is a purifying, rather than afflictive fire. Mortal sin deprives us of communion with God, and this deprivation is eternal punishment in Hell. The suffering in Purgatory, on the other hand, is that of yearning for God, and it is not God’s vengeance, and the Church has always commended almsgiving and prayers for those who are in Purgatory.
The Limbo of the unbaptized infants is something that scholars and saints have had myriad opinions on, with a variety of beliefs such as (1) unbaptized infants go to Hell, (2) that the infants go to Hell, but do not have the torments of Hell, (3) that they live on the edge of Heaven, a sort of limbo, or (4) that God will save unbaptized infants, and we should trust them to God’s grace. It is not known for certain what the whole truth is, but even those who postulated Limbo believe that parents may save their children by desiring baptism for them.
Even from Old Testament times, there have been writings of an intermediary place between Heaven and Earth, such as Wisdom 3, Psalms 6:5, 88:12, 94:17, Job 10:21f, Job 14:21 and these are confirmed by the saints, like St. Irenaeus. We know that this place has no knowledge of the world, but it is clear from I Sam 2:6, Job 26:6 and Psalms 86:13, 139:8 that God is still present in this place, and from Christ’s statement that God is the God of the living, not of the dead.
One of these intermediary places is often called hell, taken from the Old English word for the place of the dead, but it is not the Hell of damnation. We know from scripture that Christ rose from the dead, which indicates that He had descended as savior and Christus Victor to the nether world to proclaim the Gospel to the just imprisoned there (see Jn 5:25, 1 Pet 3:18-20 and 1 Pet 4:6 as well as Sections 632f of the Catechism).
This harrowing takes place in time, even though it may seem to us as though it takes place in an instant and after this, Christ holds the keys of death and Hades. Jesus came to Earth, took on the flesh of one of His creation, like us, died like we do, and then, through rising, saves us (see also Heb 2:14-18).