Opus Operantis (Lat. literally the work of the worker), a well-known theological phrase, intended to signify that the effect of a particular ministration or rite is primarily and directly due, not to the rite itself (opus), but to the disposition of the subject (operans). Thus, in the act of kissing or praying before a crucifix, of sprinkling one's self with holy water, of telling the prayers of the rosary upon blessed beads, the fervor and personal piety of the supplicant, and not the material object of the religious use, is held to be, the efficient cause of the grace which is thereby imparted. The term is used chiefly by writers of the Roman Catholic schools, in whose system, however, the sacramental rites are held to differ from all others in this respect. SEE OPUS OPERATUM.