Devotion to the Sacred Heart of Jesus has existed for centuries with it appearing in records from 11th and 12th centuries. It has been extremely popular with saints and one in particular, St. Margaret Mary Alacoque, saw visions of Our Lord, conversed with him and was instructed to establish and promote it further. You can read more about the Sacred Heart of Jesus here and St. Margaret Mary here.
In this devotion we commemorate and celebrate our Lord's humanity as well as his divinity. We see vividly in his heart how his great his love is for us and what he was prepared to undergo in order to reconcile us to God. But had Jesus been purely man then this sacrifice would have never sufficed, in his heart, in the various devotions to the Sacred Heart, we see the awesome, spine-tingling mystery of how he was God and man, how his human heart was pierced by a lance on the Cross and in his divinity his heart took on all of our sins and paid the price for them. Why not, today, pray the Litany of the Sacred Heart or the prayer below either in thanksgiving for God's wonderful gift to us or for your own intentions?
O, Sacred Heart of Jesus,
filled with Infinite Love, broken by our ingratitude, and pierced by our sins, yet loving us still, accept the consecration we make to Thee of all that we are and all that we have. Take every faculty of our souls and bodies, only day by day draw us nearer and nearer to Thy Sacred Heart, and there, as we shall hear the lesson, teach us Thy Holy Way. Amen.