In honor of St. Robert Bellarmine we have today from his de Sacramento Baptismi a very fine definition and explanation of the Sacrament of Baptism:
|Quod autem attinet ad definitionem, s. Thomas 3. par. quaest. 66. art. 1. aliquot definitiones adfert. Sed ex Scripturis catechismus romanus aptissime ita definivit: Baptismus est sacramentum regenerationis per aquam in verbo vitae. Quae definitio partim sumitur ex Joan. 3. partim ex Paulo ad Ephes. 5. Et quidem primo loco ponitur, Sacramentum, quod est genus. Deinde additur, regenerationis, quae differentia est contrahens genus, et distinguiens a sacramentis veteris legis. Tertio additur, per aquam, quae est alia differentia, adhuc magis contrahens, et distinguiens ab aliis sacramentis novae legis. Etsi enim caetera non dicuntur proprie regenerare, tamen justificant impium, ac praesertim Poenitentia: justificatio autem impii, praesertim haeretici, aut apostatae, parum aut nihil differt a regeneratione. Unde Galat. 4. Paulus, Filioli mei, quos iterum parturio. Sed cum additur, per aquam, jam perspicua differentia est. Non enim reconciliatio poenitentium est regeneratio per aquam, sed reformatio quaedam, et quasi revocatio ab inferis.||Regarding the definition of this Sacrament, St. Thomas in III 66 3 1 gives several definitions. But from the Scriptures, the Roman Catechism very aptly defines it thus: Baptism is the sacrament of regeneration through water in the word of life. This definition is taken in part from John 3, partly from Paul in Eph 5. The first word, Sacrament, gives the genus. Then of regeneration is added, which is the difference that clarifies the genus, and distinguishes it from the sacraments of the Old Law. Third, through water is added, which is the other difference and clarifies more, distinguishing [this Sacrament] from the other sacraments of the New Law. For even if the other [Sacraments] are not properly said to regenerate, yet they do justify the sinner, especially Penance: and the justification of the sinner, especially the heretic or apostate, differs little or none from regeneration. Thus Paul says in Galatians 4, “My little children, with whom I am again in travail until Christ be formed in you!” But when through water is added, the difference becomes clear. Reconciliation of penitents is not a regeneration through water, but a certain reformation, like calling someone back from hell.|
 NB ‘vitae’ seems to be added by Bellarmine as it is missing in the Roman Catechism, and in Eph 5:26.