Objection 1. It would seem that the resurrection will not be for all without exception. For it is written (Psalm 1:5): "The wicked shall not rise again in judgment." Now men will not rise again except at the time of the general judgment. Therefore the wicked shall in no way rise again.
Objection 2. Further, it is written (Daniel 12:2): "Many of those that sleep in the dust of the earth shall awake." But these words imply a restriction. Therefore all will not rise again.
Objection 3. Further, by the resurrection men are conformed to Christ rising again; wherefore the Apostle argues (1 Corinthians 15:12, seqq.) that if Christ rose again, we also shall rise again. Now those alone should be conformed to Christ rising again who have borne His image, and this belongs to the good alone. Therefore they alone shall rise again.
Objection 4. Further, punishment is not remitted unless the fault be condoned. Now bodily death is the punishment of original sin. Therefore, as original sin is not forgiven to all, all will not rise again.
Objection 5. Further, as we are born again by the grace of Christ, even so shall we rise again by His grace. Now those who die in their mother's womb can never be born again: therefore neither can they rise again, and consequently all will not rise again.
On the contrary, It is said (John 5:28,35): "All that are in the graves shall hear the voice of the Son of God... and they that hear shall live." Therefore the dead shall all rise again.
Further, it is written (1 Corinthians 15:51): "We shall all indeed rise again," etc.
Further, the resurrection is necessary in order that those who rise again may receive punishment or reward according to their merits. Now either punishment or reward is due to all, either for their own merits, as to adults, or for others' merits, as to children. Therefore all will rise again.
I answer that, Those things, the reason of which comes from the nature of a species, must needs be found likewise in all the members of that same species. Now such is the resurrection: because the reason thereof, as stated above (Article 1), is that the soul cannot have the final perfection of the human species, so long as it is separated from the body. Hence no soul will remain for ever separated from the body. Therefore it is necessary for all, as well as for one, to rise again.
Reply to Objection 1. As a gloss expounds these words, they refer to the spiritual resurrection whereby the wicked shall not rise again in the particular judgment. or else they refer to the wicked who are altogether unbelievers, who will not rise again to be judged, since they are already judged [John 3:18].
Reply to Objection 2. Augustine (De Civ. Dei xx, 23) explains "many" as meaning "all": in fact, this way of speaking is often met with in Holy Writ. Or else the restriction may refer to the children consigned to limbo who, although they shall rise again, are not properly said to awake, since they will have no sense either of pain or of glory, and waking is the unchaining of the senses.
Reply to Objection 3. All, both good and wicked, are conformed to Christ, while living in this life, as regards things pertaining to the nature of the species, but not as regards matters pertaining to grace. Hence all will be conformed to Him in the restoration of natural life, but not in the likeness of glory, except the good alone.
Reply to Objection 4. Those who have died in original sin have, by dying, discharged the obligation of death which is the punishment of original sin. Hence, notwithstanding original sin, they can rise again from death: for the punishment of original sin is to die, rather than to be detained by death.
Reply to Objection 5. We are born again by the grace of Christ that is given to us, but we rise again by the grace of Christ whereby it came about that He took our nature, since it is by this that we are conformed to Him in natural things. Hence those who die in their mother's womb, although they are not born again by receiving grace, will nevertheless rise again on account of the conformity of their nature with Him, which conformity they acquired by attaining to the perfection of the human species.
Source: Summa Theologica (New Advent)