“The prayer of the Church venerates and honors the Heart of Jesus…which, out of love for men, he allowed to be pierced by our sins.” (CCC)
Devotion to the Sacred Heart of Jesus can be found throughout the history of the Church. It took the mystical revelations of a French nun, St. Margaret Mary Alacoque, however, to make this devotion widespread. In 1675, within the octave of the feast of Corpus Christi, our Lord appeared to her and said: “Behold this heart which, notwithstanding the burning love for men with which it is consumed and exhausted, meets with no other return from most Christians than sacrilege, contempt, indifference and ingratitude, even in the sacrament of my love [the Eucharist]. ” 
To those who show him love and who make reparation for sins, however, our Lord made a great pledge: “I promise you in the unfathomable mercy of my heart that my omnipotent love will procure the grace of final penitence for all those who receive communion on nine successive first Fridays of the month; they will not die in my disfavor, or without having received the sacraments, since my divine heart will be their sure refuge in the last moments of their life.”
The great promise of the Sacred Heart is most consoling: the grace of final perseverance and the joy of having Jesus’ heart as our sure refuge and Infinite Ocean of mercy in our last hour.
“I promise you, in the excessive mercy of my Heart that my all powerful love will grant to all those who receive Holy Communion on the first Friday for nine consecutive months, the grace of final repentance; they shall not die in my disgrace nor without receiving the sacraments; my divine Heart shall be their safe refuge in that last moment.” — Our Lord to St. Margaret Mary
To gain this grace, we must:
- Receive holy Communion on nine consecutive first Fridays.
- Have the intention of honoring the Sacred Heart of Jesus and of reaching final perseverance.
- Offer each holy Communion as an act of atonement for offenses against the Blessed Sacrament.
Almighty and everlasting God, look upon the heart of your well-beloved Son and upon the praise and satisfaction which he offers to you in the name of all sinners; and grant them pardon when they seek your mercy. We ask this in the name of Jesus Christ, your Son, who lives and reigns with you for ever and ever.
Act of Reparation to the Sacred Heart of Jesus
Sacred Heart of Jesus, animated with a desire to repair the outrages unceasingly offered to Thee, we prostrate before Thy throne of mercy, and in the name of all mankind, pledge our love and fidelity to Thee!
The more Thy mysteries are blasphemed, the more firmly we shall believe them, O Sacred Heart of Jesus!
The more impiety endeavors to extinguish our hopes of immortality, the more we shall trust in Thy Heart, sole hope of mankind!
The more hearts resist Thy Divine attractions, the more we shall love Thee, O infinitely amiable Heart of Jesus!
The more unbelief attacks Thy Divinity, the more humbly and profoundly we shall adore It, O Divine Heart of Jesus!
The more Thy holy laws are transgressed and ignored, the more we shall delight to observe them, O most holy Heart of Jesus!
The more Thy Sacraments are despised and abandoned, the more frequently we shall receive them with love and reverence, O most liberal Heart of Jesus!
The more the imitation of Thy virtues is neglected and forgotten, the more we shall endeavor to practice them, O Heart of Jesus, model of every virtue!
The more the devil labors to destroy souls, the more we shall be inflamed with desire to save them, O Heart of Jesus, zealous Lover of souls!
The more sin and impurity destroy the image of God in man, the more we shall try by purity of life to be a living temple of the Holy Spirit, O Heart of Jesus!
The more Thy Holy Church is despised, the more we shall endeavor to be her faithful children, O Sweet Heart of Jesus!
The more Thy Vicar on earth is persecuted, the more we will honor him as the infallible head of Thy Holy Church, show our fidelity and pray for him, O kingly Heart of Jesus!
O Sacred Heart, through Thy powerful grace, may we become Thy apostles in the midst of a corrupted world, and be Thy crown in the kingdom of heaven. Amen.
12 Promises of the Sacred Heart to St. Margaret Mary
- I will give them all the graces necessary for their state of life.
- I will give peace in their families.
- I will console them in all their troubles.
- I will be their refuge in life and especially in death.
- I will abundantly bless all their undertakings.
- Sinners shall find in my Heart the source and infinite ocean of mercy.
- Tepid souls shall become fervent.
- Fervent souls shall rise speedily to great perfection.
- I will bless those places wherein the image of my Sacred Heart shall be exposed and venerated.
- I will give to priests the power to touch the most hardened hearts.
- Persons who propagate this devotion shall have their names eternally written in my Heart.
- In the excess of the mercy of my heart, I promise you that my all powerful love will grant to all those who will receive Communion on the First Fridays, for 9 consecutive months, the grace of final repentance: they will not die in my displeasure, nor without receiving the sacraments; and my Heart will be their secure refuge in that last hour.
-By Fr. Mark McGeary
 St Margeret M Alacoque, Autobiography