To read about the History: http://www.sistersofreparation.org/history-of-devotion-to-t…
"Behold this Heart, Which has loved men so much, that It has spared nothing, even to exhausting and consuming Itself, in order to testify to them Its love; and in return I receive from the greater number nothing but ingratitude by reason of their irreverence and sacrileges, and by the coldness and contempt which they show Me in this Sacrament of Love. But what I feel the most keenly is that it is hearts which are consecrated to Me that treat Me thus. Therefore, I ask of thee that the Friday after the Octave of Corpus Christi be set apart for a special feast to honour My Heart, by communicating on that day and making reparation to It by a solemn act, in order to make amends for the indignities which It has received during the time It has been exposed on the altars. I promise thee that My Heart shall expand Itself to shed in abundance the influence of Its divine love upon those who shall thus honour It, and cause It to be honored." - Jesus' Words to St. Margaret Mary