Researched by the Ignaria Editorial Team · Published 2026-04-24
The question of whether sacraments merely signify grace or actually confer it divides the medieval and Reformation traditions along a clear fault line. Hugh of St. Victor established the definitive medieval formula: a sacrament must have similitude (representing the thing), institution (ordering it to signify), and sanctification — meaning it must contain the grace it signifies and be efficacious in conferring that grace on those who receive it. Peter Lombard sharpened this into the distinction between a bare sign and an efficacious sign: ordination, baptism, and the Eucharist do not merely point to grace but bring about what they signify. Aquinas grounded this in Christ's passion, treating the sacraments as instruments through which the effects of that passion are causally applied to believers. Calvin did not dismiss sacraments — he insisted they are more than empty gestures — but he reframed their efficacy: sacraments are external signs by which God seals his promises on our consciences to sustain weak faith, appendixes to the word rather than independent channels. For Calvin, the substance flows from the promise; the rite confirms it for human weakness. This distinction — grace conferred through the rite versus grace confirmed by the rite — remains the central axis around which Catholic, Orthodox, and Protestant views of worship and salvation continue to orbit.
What the primary sources show
"A sacrament is a sign of the grace of God and the form of invisible grace, in such a way as to carry its image and to be its cause." Lombard's definition is the pivot of medieval sacramental theology: sacraments are not merely signs but efficacious causes — they bring about the invisible grace they represent. This formula shaped Aquinas, Trent, and every subsequent Catholic account of sacramental power.
"It seems to me a simple and appropriate definition to say that a sacrament is an external sign, by which the Lord seals on our consciences his promises of good-will toward us, in order to sustain the weakness of our faith." Calvin's counter-definition preserves the seriousness of the rites while relocating efficacy: the sign confirms a prior promise rather than conveying grace independently of it. This reframing drove the wedge between Protestant and Catholic accounts of the sacraments.