The human heart has been a symbol of love, and a metaphor for the innermost essence of things. In the Roman Catholic tradition, the physical, mystical heart of Jesus is an object of popular devotion. The Sacred Heart of Jesus is celebrated on the Friday of the third week after Pentecost (June 7 this year), and also every first Friday and the entire month of June.
This devotion includes acts of honor and reparation to the Sacred Heart, depicted as a radiant yet wounded heart, encircled by a crown of thorns. The devotion, promoted by St. Francis de Sales and some religious orders, became especially popular due to the visions of Saint Margaret Mary Alacoque in the late 17th century. It’s a response to the religious indifference or confusion at the time, and an antidote to Jansenism, a popular heresy, that emphasized human sinfulness and sense of guilt.
While this devotion and the Divine Mercy are both about God’s mercy, the Sacred Heart is about the Son of God with the call for reparations, and the Divine Mercy is about the Holy Trinity with a spirit of trust. The feast of the Sacred Heart became universal in 1856 during the reign of Blessed Pius IX, and the Divine Mercy Sunday was instituted in 2000 by Saint John Paul II.