83 Devotion to Christ’s heart is essential for our Christian life to the extent that it expresses our openness in faith and adoration to the mystery of the Lord’s divine and human love. In this sense, we can once more affirm that the Sacred Heart is a synthesis of the Gospel. We need to remember that the visions or mystical showings related by certain saints who passionately encouraged devotion to Christ’s heart are not something that the faithful are obliged to believe as if they were the word of God. Nonetheless, they are rich sources of encouragement and can prove greatly beneficial, even if no one need feel forced to follow them should they not prove helpful on his or her own spiritual journey. At the same time, however, we should be mindful that, as Pius XII pointed out, this devotion cannot be said “to owe its origin to private revelations”.
Source: Dilexit Nos (Vatican.va)