St. John Eudes was among the many promoters of devotion to the Sacred Heart over the centuries. He was a 17th-century priest in France who was deeply impacted by St. Francis de Sales.
Here is one of St. John Eudes' prayers that he used to help promote devotion to the Sacred Heart.
O Heart all loveable and all loving of my Savior, be the Heart of my heart, the Soul of my soul, the Spirit of my spirit, the Life of my life and the sole principle of all my thoughts, words and actions, of all the faculties of my soul and of all my senses, both interior and exterior. Amen.