I answer that, The character of Confirmation, of necessity supposes the baptismal character: so that, in effect, if one who is not baptized were to be confirmed, he would receive nothing, but would have to be confirmed again after receiving Baptism. The reason of this is that, Confirmation is to Baptism as growth to birth, as is evident from what has been said above (A. 1; Q. 65, A. 1). Now it is clear that no one can be brought to perfect age unless he be first born: and in like manner, unless a man be first baptized, he cannot receive the sacrament of Confirmation.
Reply Obj. 1: The Divine power is not confined to the sacraments. Hence man can receive spiritual strength to confess the Faith of Christ publicly, without receiving the sacrament of Confirmation: just as he can also receive remission of sins without Baptism. Yet, just as none receive the effect of Baptism without the desire of Baptism; so none receive the effect of Confirmation, without the desire of Confirmation. And man can have this even before receiving Baptism.
Reply Obj. 2: As Augustine says (Ep. cclxv), from our Lord's words, "'He that is washed, needeth not but to wash his feet' (John 13:10), we gather that Peter and Christ's other disciples had been baptized, either with John's Baptism, as some think; or with Christ's, which is more credible. For He did not refuse to administer Baptism, so as to have servants by whom to baptize others."
Reply Obj. 3: Those who heard the preaching of Peter received the effect of Confirmation miraculously: but not the sacrament of Confirmation. Now it has been stated (ad 1) that the effect of Confirmation can be bestowed on man before Baptism, whereas the sacrament cannot. For just as the effect of Confirmation, which is spiritual strength, presupposes the effect of Baptism, which is justification, so the sacrament of Confirmation presupposes the sacrament of Baptism. _______________________
SEVENTH ARTICLE [III, Q. 72, Art. 7]
Whether Sanctifying Grace Is Bestowed in This Sacrament?
Objection 1: It seems that sanctifying grace is not bestowed in this sacrament. For sanctifying grace is ordained against sin. But this sacrament, as stated above (A. 6) is given only to the baptized, who are cleansed from sin. Therefore sanctifying grace is not bestowed in this sacrament.
Obj. 2: Further, sinners especially need sanctifying grace, by which alone can they be justified. If, therefore, sanctifying grace is bestowed in this sacrament, it seems that it should be given to those who are in sin. And yet this is not true.
Obj. 3: Further, there can only be one species of sanctifying grace, since it is ordained to one effect. But two forms of the same species cannot be in the same subject. Since, therefore, man receives sanctifying grace in Baptism, it seems that sanctifying grace is not bestowed in Confirmation, which is given to none but the baptized.
On the contrary, Pope Melchiades says (Ep. ad Episc. Hispan.): "The Holy Ghost bestows at the font the fulness of innocence; but in Confirmation He confers an increase of grace."