June is dedicated to the Sacred Heart of Jesus in the Catholic Church.
Many saints promoted this devotion, including Saints Margaret Mary Alacoque, Gertrude the Great, Francis de Sales, Gemma Galgani, Therese of Lisieux, and many more.
According to the Catechism of the Catholic Church, the veneration of the Heart of Jesus is a way to adore the incarnate Word and His love, “which, out of love for men, he allowed to be pierced by our sins.” (CCC 2669)
Below are several quotes from the saints honoring the Sacred Heart of Jesus:

1) “The Divine Heart is an ocean full of all good things, wherein poor souls can cast all their needs; it is an ocean full of joy to drown all our sadness, an ocean of humility to drown our folly, an ocean of mercy to those in distress, an ocean of love in which to submerge our poverty.” - Saint Margaret Mary Alacoque

2) “We are weak, but by the Heart of Jesus we shall become strong; by the charity of the Heart of Jesus we shall triumph over death and hell, and in the Heart of Jesus we shall find all the treasures of wisdom and knowledge.” - Devotion to the Sacred Heart of Jesus According to St. Gertrude by Fr. André Prévot

3) “O Jesus, Your Sacred Heart is an ocean of mercy; I immerse myself in it, trusting in Your infinite compassion.” - Saint Faustina

4) “Surely it is a source of profound consolation to know that we are loved so deeply by Our Lord, who constantly carries us in his heart.” - Saint Francis de Sales

5) “The wounds inflicted on his body have disclosed to us the secrets of his heart; they enable us to contemplate the great mystery of his compassion.” - Saint Bernard of Clarivaux

6) “What joy one experiences when one abandons oneself into the arms of Jesus! The faithful soul becomes his dearest child. He opens his arms to receive it, and presses it to his most Sacred Heart.” - Saint Gemma Galgani

7) “Ever since I have been given the grace to understand also the love of the heart of Jesus, I admit that it has expelled all fear from my heart.” Saint Therese of Lisieux

8) "O Sacred Heart of Jesus, fountain of eternal life, Your Heart is a glowing furnace of Love. You are my refuge and my sanctuary." - Saint Gertrude the Great

9) “Love overcomes, Love delights, those who love the Sacred heart rejoice!” - Saint Bernadette Soubirous

10) "No matter what my sufferings may be, I will never complain, and if I have to undergo any humiliation, I will seek refuge in the Sacred Heart of Jesus." - Saint Alphonsa of the Immaculate Conception