In his Address to the Roman Rota of 2013, almost precisely on the 30th anniversary of the promulgation of the canon law of the Catholic Church, Pope Benedict XVI firmly presented a speech concerning “an irrevocable covenant between a man and a woman”, inspired by the celebration of the Year of Faith and a peculiar commentary to the De matrimonio chapter of Canon 1055. The author of the hereby article follows the track of Benedict XVI. Within the notion of “covenant” he not only identifies the key to the contemporary doctrine of marriage, but also points out the role of the keystone in the “program” consolidation of two aspects of matrimonium canonicum: natural and supernatural. On the one hand, the internal truth of the covenant act of marital love, thus the totality of the personal gift, as well as its immanently implied irrevocability, constitute the point of reference for the material frames of the consortium totius vitae. On the other hand, what seems most inspiring is the papal statement regarding the common linguistic roots the Latin terms fides and foedus have.