An hour of mental or vocal prayer spent in veneration of the sufferings of Jesus, particularly those He endured in Gethsemane, and in worship of the love whereby He was led to institute the Eucharist. If the hour is spent in a church, or a public or semipublic oratory, a plenary indulgence may be gained under the usual conditions. The Holy Hour can be made alone or in company with others. Public Holy Hour is commonly accompanied by exposition of the Blessed Sacrament to add solemnity to the devotion. As a private devotion the preferred hour is from 11 p.m. until midnight on Thursdays, or from 2 p.m. Thursday until midnight of Friday, but it is a commendable practice at any time.
St. Margaret Mary alacoque has written the story of its origin. In 1674, very probably on the first Friday of July, she wrote "… while the Blessed Sacrament was exposed, I felt drawn within myself by an extraordinary recollection of all my senses and powers. Jesus Christ presented Himself to me all resplendent with glory… .'Every week between Thursday and Friday,[He said] I will grant you to share in that mortal sadness which I chose to feel in the Garden of Olives…. You shall keep me company in the prayer I then offered to my Father… ." Each week thereafter Margaret kept the Holy Hour.
In France the devotion was propagated by a Jesuit priest, Robert Debrosse, who in 1829 formed an association that became the Archconfraternity of the Holy Hour with its center at the Visitation Convent at Paray-le-Monial. In the U.S. a public Holy Hour often terminates a day of recollection or a retreat. Many parishes have one scheduled weekly.
Enriched with indulgences, the exercise is singularly effective for spiritual growth. Sin is presented from God's point of view and in its relation to the agony of Christ; the example of His heroic obedience is considered; the main message of the Sacred Heart is made evident: "Behold this Heart which has so loved men."
Bibliography: f. m. catherinet, Ce qu’il faut savoir pour bien comprendre et bien faire l'Heure Sainte (Paray-le-Monial 1932). k. rahner, Heilige Stunde und Passionsandacht (3d ed. Freiburg im Br. 1960).