I always saw the 17th century saint, Margaret Mary Alacoque, as the forerunner for the Sacred Heart of Jesus. In her autobiography, she wrote about the apparitions of the Sacred Heart. Christ said to Saint Margaret:

My Divine Heart is so inflamed with love for men, and for you in particular that, being unable any longer to contain within itself the flames of Its burning Charity …

Through these apparitions, Jesus revealed particular insight to Saint Mary. One of which is devotions on First Friday. He said,

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 Fridays 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.

There were also 12 promises for those who keep First Fridays in honor of the Heart of Christ. You can view those promises here.

The Holy Father reminds us of the continuity of devotion to the Sacred Heart throughout the tradition. He mentions several women saints. These include Lutgarde, Mechtilde of Hackeborn, Angela of Foligno, and Dame Julian of Norwich. They gave insight to the Sacred Heart.

The Holy Father highlights Saint Gertrude of Helfta as one of the most intimate confidants of the Sacred Heart. He points out the spiritual conversation she had with the Beloved Disciple. Saint Margaret wondered why the Gospel writer did not document his experience. He had listened to the heart of Christ during the last supper. The Beloved disciple replied:

the sweet sound of those heartbeats has been reserved for modern times, so that, hearing them, our aging and lukewarm world may be renewed in the love of God.

Saint John Eudes is attributed for taking the Sacred Heart beyond the walls of the monastery to the world. Today, we are called to take the Sacred Heart into our communities. This is the time to renew our love of Jesus. We, too, can be intimate confidants to the burning heart of Christ.