This devotion for the holy souls is traditionally prayed on Good Friday. It is to be prayed 33 times before an image of a crucifix and will release 33 souls from Purgatory.
Heart of Jesus in Whom are found all the treasures of wisdom and scientific knowledge, have mercy on us!
Pray the following 33 times:
I venerate Thee, O Holy Cross, carrying the sacred members of our Lord and reddened by His precious blood.
I adore Thee, O my God, nailed to the Holy Cross for love of me.
Jesus I trust Thee.