Today is the Solemnity of the Most Sacred Heart of Jesus:
The Sacred Heart (also known as Sacred Heart of Jesus) is one of the most famous religious devotions to Jesus’ physical heart as the representation of His divine love for Humanity.
This devotion is predominantly used in the Catholic Church and among some high-church Anglicans. The devotion especially emphasizes the unmitigated love, compassion, and long-suffering of the heart of Christ towards humanity. The origin of this devotion in its modern form is derived from a French Roman Catholic nun, Marguerite Marie Alacoque, who said she learned the devotion from Jesus during a mystical experience. Predecessors to the modern devotion arose unmistakably in the Middle Ages in various facets of Catholic mysticism…
The Sacred Heart is often depicted in Christian art as a flaming heart shining with divine light, pierced by the lance-wound, surrounded by the crown of thorns, surmounted by a cross and bleeding. Sometimes the image shown shining within the bosom of Christ with his wounded hands pointing at the heart. The wounds and crown of thorns allude to the manner of Jesus’ death, while the fire represents the transformative power of divine love.
The Feast of the Sacred Heart has been a Solemnity in the Roman Catholic liturgical calendar since 1856, and is celebrated 19 days after Pentecost. As Pentecost is always celebrated on Sunday, the Feast of the Sacred Heart always falls on a Friday.
More here.
And here is an appropriate Act of Reparation for today:
Most sweet Jesus, whose overflowing charity for men is requited by so much forgetfulness, negligence and contempt, behold us prostrate before Thee, eager to repair by a special act of homage the cruel indifference and injuries to which Thy loving Heart is everywhere subject.
Mindful, alas! that we ourselves have had a share in such great indignities, which we now deplore from the depths of our hearts, we humbly ask Thy pardon and declare our readiness to atone by voluntary expiation, not only for our own personal offenses, but also for the sins of those, who, straying far from the path of salvation, refuse in their obstinate infidelity to follow Thee, their Shepherd and Leader, or, renouncing the promises of their baptism, have cast off the sweet yoke of Thy law.

We are now resolved to expiate each and every deplorable outrage committed against Thee; we are now determined to make amends for the manifold offenses against Christian modesty in unbecoming dress and behavior, for all the foul seductions laid to ensnare the feet of the innocent, for the frequent violations of Sundays and holydays, and the shocking blasphemies uttered against Thee and Thy Saints. We wish also to make amends for the insults to which Thy Vicar on earth and Thy priests are subjected, for the profanation, by conscious neglect or terrible acts of sacrilege, of the very crimes of nations who resist the rights and teaching authority of the Church which Thou hast founded.
Would that we were able to wash away such abominations with our blood. We now offer, in reparation for these violations of Thy divine honor, the satisfaction Thou once made to Thy Eternal Father on the cross and which Thou continuest to renew daily on our altars; we offer it in union with the acts of atonement of Thy Virgin Mother and all the Saints and of the pious faithful on earth; and we sincerely promise to make recompense, as far as we can with the help of Thy grace, for all neglect of Thy great love and for the sins we and others have committed in the past. Henceforth, we will live a life of unswerving faith, of purity of conduct, of perfect observance of the precepts of the Gospel and especially that of charity. We promise to the best of our power to prevent others from offending Thee and to bring as many as possible to follow Thee.
O loving Jesus, through the intercession of the Blessed Virgin Mother, our model in reparation, deign to receive the voluntary offering we make of this act of expiation; and by the crowning gift of perseverance keep us faithful unto death in our duty and the allegiance we owe to Thee, so that we may all one day come to that happy home, where with the Father and the Holy Spirit Thou livest and reignest, God, forever and ever.
Amen.