In 2008 and 2020, the Congregation for the Doctrine of the Faith published two responses to questions posed regarding the validity of modified baptismal formulas. When administering baptism, some Catholic ministers had altered the prescribed formula with regard to the naming of the Trinity and with regard to the declarative introduction of the formula (ie ‘We baptise you …’ instead of ‘I baptise you …’). The Congregation dismissed all of these formulas as invalidating baptism and demanded that individuals baptised with these formulas be baptised again. In explaining its 2020 response the Congregation referred to Thomas Aquinas, who addressed these and similar issues in his sacramental theology. This reference is evidently due to Aquinas’ pioneering thoughts on the issue. However, in studying Aquinas’ work on the subject it is surprising to find that they reveal a far less literalist approach than the Congregation suggests. In fact, his considerations point at an alternative reading, namely that sacramental formulas should be understood as acts of communication which, based on the ministers’ intention of doing what the Church does, aim at communicating God's grace to the receivers in an understandable way.