Mystici Corporis Christi §80

⁸⁰ Therefore, Our most learned predecessor Leo XIII of happy memory, speaking of our union with Christ and with the Divine Paraclete who dwells within us, and fixing his gaze on that blessed vision through which this mystical union will attain its confirmation and perfection in heaven says: "This wonderful union, or indwelling properly so-called, differs from that by which God embraces and gives joy to the elect only by reason of our earthly state." In that celestial vision it will be granted to the eyes of the human mind strengthened by the light of glory, to contemplate the Father, the Son, and the Holy Spirit in an utterly ineffable manner, to assist throughout eternity at the processions of the Divine Persons, and to rejoice with a happiness like to that with which the holy and undivided Trinity is happy.