122 It is likewise Our most fervent desire that all who profess themselves Christians and are seriously engaged in the effort to establish the kingdom of Christ on earth will consider the practice of devotion to the Heart of Jesus as the source and symbol of unity, salvation and peace. Let no one think, however, that by such a practice anything is taken from the other forms of piety with which Christian people, under the guidance of the Church, have honored the divine Redeemer. Quite the opposite. Fervent devotional practice towards the Heart of Jesus will beyond all doubt foster and advance devotion to the Holy Cross in particular, and love for the Most Holy Sacrament of the Altar. We can even assert - as the revelations made by Jesus Christ to St. Gertrude and to St. Margaret Mary clearly show - that no one really ever has a proper understanding of Christ crucified to whom the inner mysteries of His Heart have not been made known. Nor will it be easy to understand the strength of the love which moved Christ to give Himself to us as our spiritual food save by fostering in a special way the devotion to the Eucharistic Heart of Jesus, the purpose of which is - to use the words of Our predecessor of happy memory, Leo XIII - "to call to mind the act of supreme love whereby our Redeemer, pouring forth all the treasures of His Heart in order to remain with us till the end of time, instituted the adorable Sacrament of the Eucharist."(122) For "not the least part of the revelation of that Heart is the Eucharist, which He gave to us out of the great charity of His own Heart."(123)
Source: Haurietis Aquas (Vatican.va)