First Friday devotions among Catholics are related to devotion to the Sacred Heart of Christ. First Friday practices date to the last decades of the 17th century, when Jesus appeared to St. Margaret Mary and spoke to her of His Sacred Heart. Among the promises Our Lord revealed to St. Margaret Mary were specifically-referenced practices for Fridays:
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 nine 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.
Devotion to the Sacred Heart, as given to St. Margaret by Jesus, began to grow in popularity as soon as the saintly woman had died, but was officially recognized 75 years later. Though the devotion dictated to Margaret referred to nine consecutive first Fridays, it does not need to end there. Many of the Catholic faithful continue to make the First Friday devotion beyond the nine consecutive months.
Holy Mass on Friday is devoted to the Sacred Heart and to the Precious Blood of Jesus. Due in part to the promise revealed by Christ to St. Margaret Mary, attending Mass on the First Friday of the month is popular among many Catholics, even if they are unable to attend daily Mass regularly throughout the week. Reception of the Holy Eucharist on such Fridays was popular even in years when frequent Communion was not. Fridays, particularly the first Friday of the month, are the popular day in many parishes for the Blessed Sacrament to be taken to the sick and homebound.
Devotion on Fridays have long existed among the faithful, even if they were not directly connected to the First Friday devotions to the Sacred Heart or were not relegated to the first Friday of a month. This is because, as each Sunday is a reminder and anniversary of Christ’s Resurrection, each Friday is a reminder and anniversary of His Sacrifice.
For example, Pope John XXIII, whose papacy lasted from 1959-1963, practiced a Friday devotion to the Precious Blood of Christ shed on the first Good Friday. Additionally, Friday is and had long been a day of penance for the faithful, not only during Lent but year-round. And some pray the Novena to the Sacred Heart over the nine consecutive First Fridays that they attend Mass.
Beginning on December 27, 1673, through 1675, Our Lord appeared to St. Margaret Mary Alacoque asking her to receive Him in Holy Communion on the first Friday of every month and to meditate on His passion from 11:00 PM to 12:00 midnight each Thursday. He also revealed to her twelve promises for all who are devoted to His Sacred Heart; he asked for a Feast of the Sacred Heart to be instituted in the liturgical calendar of the Church. Our Lord appeared to St. Margaret Mary Alacoque with twelve promises for those devoted to His Most Sacred Heart.
Promises for those devoted to the Sacred Heart
"Most Sacred Heart of Jesus, we place our trust in You"