THE HEROIC ACT IN FAVOR OF THE SOULS IN PURGATORY 

O MY GOD! for Thy greater glory, and to imitate as closely as possible the generous Heart of Jesus, my Redeemer, and also to testify my devotion to the Blessed Virgin, my Mother, who is also the Mother of the Souls in Purgatory, I place in her hands all my satisfactory works, as well as the fruit of all those which may be offered for my intention after my death, that she may apply them to the Souls in Purgatory according to her wisdom and good pleasure. Amen. http://www.catholictradition.org/Mary/heroic-act.htm

This is a most simple and efficacious way for thousands of us to release millions of souls from Purgatory, at every Mass and Communion. We should all try to practice this devotion, and the traditional Popes of old have encouraged us to do so.

The CE says: "The Heroic Act has been enriched with numerous indulgences by Benedict XIII (1728), Pius VI (1788), and Pius IX (1852). Priests who make it receive the personal privilege of gaining a plenary indulgence for a soul of their choice each time they say Mass (see PRIVILEGED ALTAR). Laymen gain a similar indulgence each time they receive Holy Communion, also each Monday they hear Mass for the departed; in both cases the usual visit to a church and prayers for the intention of the pope are required." and for wider context, 

"A decree of the Sacred Congregation of Indulgences dated 18 December, 1885, and confirmed the following day by Leo XIII, says:

The Heroic Act of Charity in favour of the souls detained in purgatory consists in this, that a member of the Church militant (Christifidelis), either using a set formula or simply by an act of his will, offers to God for the souls in purgatory all the satisfactory works which he will perform during his lifetime, and also all the suffrages which may accrue to him after his death. Many Christians devoted to the B.V. Mary, acting on the advice of the Theatine Regular Cleric Father Gaspar Olider, of blessed memory, make it a practice to deposit the said merits and suffrages as it were into the hands of the Bl. Virgin that she may distribute these favours to the souls in purgatory according to her own merciful pleasure."

Because it is easy to gain a plenary indulgence once we have made this act, we can hope to release 1000s of souls from Purgatory. It is impossible that these souls will not want to repay us, and so if we have living faith, we will not doubt that they will protect us by their intercession with God, and not allow us to have a lengthy purgatory. The CE explains: "The practice of the Heroic Act is based on the communion of saints, in virtue of which the good deeds of one member of Christ's body benefit all other members. Its meritoriousness results from the more intense charity (love of God and His suffering friends) which inspires it, and on which the intrinsic perfection of all our good deeds depends. Its heroicity arises from the willingness it involves to take upon one's self the dreadful pains of purgatory for the love of one's neighbour, although there remains the reasonable hope that God in His goodness, and the sainted souls in their gratitude, will not allow the punishment to be exacted to the full."

St. Gertrude the Great and St. Margaret Mary were encouraged to make this Heroic act by the Lord Himself. And lest the all too common temptation of the enemy that, if one offers oneself for others, there will allegedly be nothing left for us (as if the Good God were not infinitely generous, and could not fail to give us superabundantly more than we give Him), the example of St. Gertrude the Great herself, as related by Fr. Paul Sullivan, should show there is no such danger for one who makes and lives this act of charity.

"The Heroic Act consists in offering to God in favor of the Souls in Purgatory all the works of satisfaction we practice during life and all the suffrages that will be offered for us after death. If God rewards so abundantly the most trifling alms given to a poor man in His name, what an immense reward will He not give to those who offer all their works of satisfaction in life and death for the Souls He loves so dearly. This Act does not prevent priests from offering Mass for the intentions they wish, or lay people from praying for any persons or other intentions they desire. We counsel everyone to make this act ... St. Gertrude was fiercely tempted by the devil when she came to die. The evil spirit reserves a dangerous and subtle temptation for our last moments. As he could find no other ruse sufficiently clever with which to assail the Saint, he thought to disturb her beautiful peace of soul by suggesting that she would surely remain long years in the awful fires of Purgatory since, he reminded her, she had long ago made over all her suffrages to other souls. But Our Blessed Lord, not content with sending His Angels and the thousands of souls she had released to assist her, came Himself in person to drive away Satan and comfort His dear Saint. He told St. Gertrude that in exchange for all she had done for the Holy Souls, He would take her straight to Heaven and would multiply a hundredfold all her merits." http://www.sufferingsouls.com/part3.htm

Rather, there is only very much to be gained, as the Lord proved clearly to St. Gertrude. It is a simple way to assist the Holy Souls.

Wonderful! That's very edifying. God bless you and your husband, Maria Auxiliadora. A great grace for those people who died Catholic.

I made it in my youth. I had a great book called "Pilgrim's Guide to Paradise" where these and many other devotions were taught.

I just read those two Promises (I hadn't heard it before) on Catholic Tradition: http://www.catholictradition.org/Christ/divine-promises.htm

It mentions Nuns and other Religious especially should be able to do it continually and efficaciously each month. 30 Holy Communions, One Our Father and Hail Mary every day. In 50 years, one could do it for 600 souls! Imagine if a thousand Nuns and Monks did it!

Similarly, Bishops and Priests, with the Holy Mass and the Stations of the Cross could do the same, a very wonderful devotion. I feel sure adopting this practice and teaching it to others will help sanctify and save many thousands and millions of souls in the long run.

There's a great book "Prayers and Heavenly Promises", published by Tan Books, which mentions of these devotions and promises. 

https://www.tanbooks.com/index.php/prayers-and-heavenly-promises-compiled-from-approved-sources-2809.html

Thus, we can assist both the Holy Souls in Purgatory, per the CE, and even living souls, per the information on that site. 

Priests in particular should feel obliged to make the Heroic Act, as they could liberate almost any departed person from Purgatory quickly. The faithful can remember to offer every Holy Communion for the Holy Souls. We should not forget to give everything to Our Lord Jesus and His Sacred Heart through His Mother Mary and Her Immaculate Heart. That's why many formulas for the Heroic Act explicitly ask for the Blessed Mother to apply the satisfactory fruits of all our actions according to Her good pleasure.  The Heroic Act is in this way quite similar to Total Consecration. St. Montfort said it is so great a thing to help one sinner convert or liberate one soul from Purgatory, that it will surely have a great eternal reward: "It must be noted that our good works, passing through Mary's hands, are progressively purified. Consequently, their merit and their satisfactory and prayer value are also increased. That is why they become much more effective in relieving the souls in Purgatory and in converting sinners than if they did not pass through the virginal and liberal hands of Mary. Stripped of self-will and clothed with disinterested love, the little that we give to the Blessed Virgin is truly powerful enough to appease the anger of God and draw down his mercy. It may well be that at the hour of death a person who has been faithful to this devotion will find that he has freed many souls from Purgatory and converted many sinners, even though he performed only the ordinary actions of his state of life. Great will be his joy at the judgement. Great will be his glory throughout eternity."

The formula for the Heroic Act again: "O MY GOD! for Thy greater glory, and to imitate as closely as possible the generous Heart of Jesus, my Redeemer, and also to testify my devotion to the Blessed Virgin, my Mother, who is also the Mother of the Souls in Purgatory, I place in her hands all my satisfactory works, as well as the fruit of all those which may be offered for my intention after my death, that she may apply them to the Souls in Purgatory according to her wisdom and good pleasure. Amen." By making this Act, we express a readiness even to go to Purgatory longer, if necessary. But if we really live it, it very often won't be necessary. As the experience of so many shows, God will likely give us Mass and Communion before death, and the last plenary indulgence, we may well hope, will then be directly applied to us before death. But even if not, we should be ready to do so. Truly, God gives superabundantly to us even if we give Him little.