The Author highlights how the Church has always attributed particular relevance to the privacy of the encounter between the faithful and the priest in the administration of the Sacrament of Penance. The protection of what in the course of time will be defined as the “seal of the confessional” is intertwined with the historical development of the form of the Sacrament – when the progressive disappearance of public penance and the introduction of auricular confession, already generalized by the end of the twelfth century, in the form known to us today assumes particular importance – and the development of canonical discipline in its elaboration into juridical forms properly so called, and not only theological or moral. In fact, before entering into the specifics of the eminently canonical subject on hand, the violation of the sacramental seal as a crime, the Author first of all presents some theological reflections, in order the better to understand the reasons why the Church attributes this particular importance to absolute inviolability of the confessional seal. It is with the Fourth Lateran Council (1215) that a canon sanctions for the first time the moral and juridical obligation as a universal law of the Church, foreseeing grave penalties for priests who break it. The discipline of the Church in subiecta materia has always remained substantially the same, except for the specification of other types, as the absolution of one’s accomplice, way in the past, or, more recently, the extension of the violation of the seal through technical means. In canonical legislation regarding the sacramental seal, the Church, then, intends to transmit the pedagogy of the love of the Father of mercy on the one hand and on the other She desires to direct Her ministers to try to live the gift of ministerial and spiritual paternity, which enables them, in every experience of this seal-secret of the auricular dialog of confession, to be privileged witnesses of the sanctity of this sacrament after the example of Saint John of Nepomuk (1349-1393), who endured even martyrdom of blood in maintaining the importance of the absolute value of the inviolability of the seal of confession. Therefore not even the death of the penitent can release the confessor from this bond. The law of the sacramental seal does not admit any exceptions. No confessor can be dispensed from it, even if in wanting to reveal the contents of a confession he intends to avoid a grave and imminent evil. The sacramental seal, understood in this way, also becomes a guarantee of the marvels of God in the heart of every individual penitent, who entrusts himself to the heart of the pastors, who echo in the existential here and now of each one the beauty of the merciful and transforming Love of the Father, given by the redeeming sacrifice of Christ.