109 Gradually, the wounded side of Christ, as the abode of his love and the wellspring of the life of grace, began to be associated with his heart, especially in monastic life. We know that in the course of history, devotion to the heart of Christ was not always expressed in the same way, and that its modern developments, related to a variety of spiritual experiences, cannot be directly derived from the mediaeval forms, much less the biblical forms in which we glimpse the seeds of that devotion. This notwithstanding, the Church today rejects nothing of the good that the Holy Spirit has bestowed on us down the centuries, for she knows that it will always be possible to discern a clearer and deeper meaning in certain aspects of that devotion, and to gain new insights over the course of time.
Source: Dilexit Nos (Vatican.va)