From a letter by St. Margaret Mary:
"For the Sacred Heart is an inexhaustible fountain and its sole desire is to pour itself out into the hearts of the humble so as to free them and prepare them to lead lives according to his good pleasure.
From this divine heart three streams flow endlessly. The first is the stream of mercy for sinners; it pours into their hearts sentiments of contrition and repentance. The second is the stream of charity which helps all in need and especially aids those seeking perfection to find the means of surmounting their difficulties. From the third stream flow love and light for the benefit of his friends who have attained perfection; these he wishes to unite to himself so that they may share his knowledge and commandments and, in their individual ways, devote themselves wholly to advancing his glory.
This divine heart is an abyss of all blessings, and into it the poor should submerge all their needs. It is an abyss of joy in which all of us can immerse our sorrows. It is an abyss of lowliness to counteract our foolishness, an abyss of mercy for the wretched, an abyss of love to meet our every need."
While we're at it, here's St. Margaret Mary herself, in the Shrine of the Sacred Heart in Paray le Monial, France.