Pope Pius XII, Haurietis Aquas, encyclical on devotion to the Sacred Heart, May 15, 1956: “93. But if men have always been deeply moved by the pierced Heart of the Savior to a worship of that infinite love with which He embraces mankind -- since the words of the prophet Zacharias, ‘They shall look on Him Whom they have pierced,’[Zac. 12:10] referred by St. John the Evangelist to Jesus nailed to the Cross [Jn. 19:37], have been spoken to Christians in all ages -- it must yet be admitted that it was only by a very gradual advance that the honors of a special devotion were offered to that Heart as depicting the love, human and divine, which exists in the Incarnate Word.
94. But for those who wish to touch on the more significant stages of this devotion through the centuries, if we consider outward practice, there immediately occur the names of certain individuals who have won particular renown in this matter as being the advance guard of a form of piety which, privately and very gradually, has gained more and more strength in religious congregations. To cite some examples in establishing this devotion to the Sacred Heart of Jesus and continuously promoting it, great service was rendered by St. Bonaventure, St. Albert the Great, St. Gertrude, St. Catherine of Siena, Blessed Henry Suso, St. Peter Canisius, St. Francis de Sales. St. John Eudes was responsible for the first liturgical office celebrated in honor of the Sacred Heart of Jesus whose solemn feast, with the approval of many Bishops in France, was observed for the first time on October 20th, 1672.”