Devotion to the Sacred Heart of Jesus came into the Catholic faith through a Catholic sister known as Saint Margaret Mary Alacoque.
(1647-1690). At the age of 24, Margaret Mary entered the Visitation convent at Paray-le-Monial in France. She began to have visions of Our Lord and on December 27, 1673, on the Feast of St. John, she began to have visions that lasted for eighteen months. Jesus told her that she was to become his instrument in spreading devotion to his Sacred Heart. While kneeling before the Blessed Sacrament, Our Lord appeared to her and invited her to "rest a long time on His Divine Breast". Jesus revealed to her the marvels of the love that His Sacred Heart had for mankind.
Jesus said to her: "MY DIVINE HEART IS SO FULL OF LOVE FOR MEN AND FOR YOU IN PARTICULAR THAT, NO LONGER ABLE TO CONTAIN WITHIN ITSELF THE FLAMES OF ITS BURNING CHARITY, IT MUST SPREAD THESE FLAMES BY MEANS OF YOU, AND IT MUST MANIFEST ITSELF TO MEN IN ORDER TO ENRICH THEM WITH ITS PRECIOUS TREASURES. I HAVE CHOSEN YOU TO ACHIEVE THIS GRAND CRUSADE OF LOVE."
Saint Margaret Mary had frequent visions of the Sacred Heart of Jesus. According to Saint Margaret Mary, His Divine Heart was "more radiant than the sun and as transparent as crystal," with its adorable wound visible, and as a "furnace" of burning flames.
In June, 1675: during the feast of Corpus Christi, while praying before Our Lord in the Most Blessed Sacrament of the Monstrance. Our Lord revealed His Heart to her and said: "HERE IS THE HEART THAT HAS SO LOVED MEN AS TO SPARE NOTHING FOR THEM, EXHAUSTING AND CONSUMING ITSELF IN ORDER TO PROVE ITS LOVE FOR THEM; AND IN RETURN I RECEIVE, FROM MOST OF THEM, ONLY INGRATITUDE."
Jesus asked her to have a special feast established in honor of His Sacred Heart on the Friday after the feast of Corpus Christi. Jesus asked his followers to receive Holy Communion on that day and to make atonement for the sins of the world by an act of reparation.
Jesus asked her to have an image made of His Sacred Heart and to have it promoted throughout the world with special promises to those souls who would display His image of His Sacred Heart.
She consulted with her enlightened spiritual director whom God had given her. On the following Friday, June 21, Father de la Colombiere, her priest-director, and Saint Margaret Mary consecrated themselves to the Sacred Heart. With great sufferings and humiliations, Father de la Colombiere and Saint Margaret Mary made every effort to spread the new devotion to the Sacred Heart of Jesus.
The Lord Jesus revealed to Saint Margaret Mary the following promises to those souls who would honor the Most Sacred Heart of Jesus:
"1. I will give them all the graces necessary in their state of life.
"2. I will establish peace in their homes.
"3. I will comfort them in all their afflictions.
"4. I will be their secure refuge during life and above all in death.
"5. I will bestow a large blessing upon all their undertakings.
"6. Sinners shall find in My Heart the source and the infinite ocean of mercy.
"7. Tepid souls shall grow fervent.
"8. Fervent souls shall quickly mount to high perfection.
"9. I will bless every place where a picture of My Heart shall be set up and honored.
"10. I will give to priests the gift of touching the most hardened hearts.
"11. Those who shall promote this devotion shall have their names written in My Heart, never to be blotted out.
"12. I promise you in the excessive mercy of My Heart that My all-powerful love will grant to all those who communicate on the first Friday in nine consecutive months, the grace of final perseverance; they shall not die in My disgrace nor without receiving their Sacraments; My Divine Heart shall be their safe refuge in this last moment."
More Information on the Sacred Heart of Jesus and Devotions to the Sacred Heart