As Bonaventure begins his treatment on the sacraments, which make up the first part of his Commentary on the Sentences - Book Four, he references the second part of Book Four, the final manifestation of glory, his eschatology. So Book Four is divided into two parts. The first part treats the sacraments “according to the health they provide.” The second part considers the “glory toward which they dispose.”
These two parts are integrally connected. The first part signals that sacraments are curative, medicinal, and restorative of health, and that they overcome the weakness of sin, original and personal. In this respect, sacraments dispose the Christian to the final glory promised. Sacraments therefore have eschatological significance, pointing beyond themselves into the glory of God.
Distinction One, “which defines the sacraments in general,” moves then to address questions of institution, signification, content, efficacy, the difference between the Old and New sacraments, and the grace conferred. Bonaventure’s argument for the institution of sacraments begins, not in reference to the actions of Christ, but rather in reference to an understanding of God’s mercy and the human need for help to overcome the brokenness of sin. Sacraments provide ways to health (salus). Thus, he writes that the institution of sacraments is most fitting for God and for the need of humankind.
Furthermore, in the institution of sacraments, God takes into consideration the totality of human nature. An appropriate and curative medicine must be comprised of something corporeal and spiritual, visible and invisible. Both of these elements are necessary simply by “reason of congruity.” Bonaventure does not hold that the institution of sacraments was because of necessity on the part of God or out of absolute necessity for salvation on the part of people desiring salvation. However, sacraments “are advantageous” for healing from the effects of sin and for aiding the Christian toward the fullness of eschatological glory.
In Bonaventure’s thinking, it becomes clear: it is God, not the sacraments in and of themselves, who effectively causes grace in the soul. Sacraments dispose one to the grace God wills to give. And so sacraments are vitally important for training and for the cultivation of a desire and an openness to receive God’s grace. In a certain way, reception of sacraments calls forth a discipline, especially humility, provides insight for overcoming the ignorance of sin, and ultimately invites one into the mystical contemplation of God’s healing love.
In terms of defining or identifying the nature of a sacrament, Bonaventure moves forward with Augustine and Hugh of St. Victor. He inherited from them that a sacrament is a “sign of something sacred,” and “is instituted for the sake of signifying.” Signification is essential to a sacrament. Bonaventure makes this his own when he responds by emphasizing that “sacramental medicine has of its integrity signification. This is common and essential to all the sacraments.” Thus, the external sign and its natural signification, confirmed by institution, is Bonaventure’s starting point for searching out an understanding of all the sacraments. Thus, the external sign is the starting point for understanding the unique internal grace received in a specific sacrament. He is explicit that one does not proceed “vice versa.” One does not move from the internal grace received to the external sign in order to understand the nature of a specific sacrament.
Distinction Two is much shorter. It questions when the sacraments were instituted. Bonaventure follows the De sacramentis of Hugh of St. Victor very closely as he addresses this question. He writes, “Because the time for the remedy began at the fall, advanced in the Law, and was consummated in the Gospel, all three ages are appropriate for their institution, but yet only more or less appropriate.” And so, Bonaventure will conclude, it is appropriate that the sacraments be instituted in different times according to the salvific needs found in the different periods of salvation history.