Objection 1. It would seem that all will be equally impassible. For a gloss on 1 Corinthians 15:42, "It is sown in corruption," says that "all have equal immunity from suffering." Now the gift of impassibility consists in immunity from suffering. Therefore all will be equally impassible.
Objection 2. Further, negations are not subject to be more or less. Now impassibility is a negation or privation of passibility. Therefore it cannot be greater in one subject than in another.
Objection 3. Further, a thing is more white if it have less admixture of black. But there will be no admixture of passibility in any of the saints' bodies. Therefore they will all be equally impassible.
On the contrary, Reward should be proportionate to merit. Now some of the saints were greater in merit than others. Therefore, since impassibility is a reward, it would seem to be greater in some than in others.
Further, impassibility is condivided with the gift of clarity. Now the latter will not be equal in all, according to 1 Corinthians 15:41. Therefore neither will impassibility be equal in all.
I answer that, Impassibility may be considered in two ways, either in itself, or in respect of its cause. If it be considered in itself, since it denotes a mere negation or privation, it is not subject to be more or less, but will be equal in all the blessed. on the other hand, if we consider it in relation to its cause, thus it will be greater in one person than in another. Now its cause is the dominion of the soul over the body, and this dominion is caused by the soul's unchangeable enjoyment of God. Consequently in one who enjoys God more perfectly, there is a greater cause of impassibility.
Reply to Objection 1. This gloss is speaking of impassibility in itself and not in relation to its cause.
Reply to Objection 2. Although negations and privations considered in themselves are not increased nor diminished, yet they are subject to increase and diminution in relation to their causes. Thus a place is said to be more darksome from having more and greater obstacles to light.
Reply to Objection 3. Some things increase not only by receding from their contrary, but also by approach to a term: thus light increases. Consequently impassibility also is greater in one subject than in another, although there is no passibility remaining in any one.
Source: Summa Theologica (New Advent)