The Heart of Our Lord is the natural object of our devotion for two reasons: 1) since it was a part of His Sacred Body, the Body of the God-Man, it is the object of our adoration, that special worship we give to God alone, and 2) because the Heart is usually the symbol of love. The Heart of Our Lord reminds us of the burning love which He has in his Heart for each and every one of us – a love which was consummated in His death on the Cross for our sins. The devotion to the Heart of Our Lord was encouraged by Jesus Himself in 1673-74, when he appeared 18 times to a French Nun, who came to be known as St. Margaret Mary Alacoque.
He showed her His Heart, in the form so familiar to us now. Through statues and holy pictures, entwined with thorns, symbolizing the sufferings His Heart endured for our sins, and with flames coming from the Heart, the sign of His tremendous love for us. Our Lord asked St. Margaret Mary to reveal these things through her spiritual director. During the final apparition in 1675, our Lord said, pointing to His Heart, “Behold the Heart which has so much-loved men that it has spared nothing, even exhausting and consuming itself in testimony of its love. Instead of gratitude I receive from most only indifference, by irreverence and sacrilege and the coldness and scorn that people have for me in the sacrament of love.” (The Holy Eucharist)