90 We are convinced, then, that the devotion which We are fostering to the love of God and Jesus Christ for the human race by means of the revered symbol of the pierced Heart of the crucified Redeemer has never been altogether unknown to the piety of the faithful, although it has become more clearly known and has spread in a remarkable manner throughout the Church in quite recent times. Particularly was this so after our Lord Himself had privately revealed this divine secret to some of His children to whom He had granted an abundance of heavenly gifts, and whom He had chosen as His special messengers and heralds of this devotion.
Source: Haurietis Aquas (Vatican.va)