Once we comprehend the Son, remaining in His Love, and grasp the Word of God expressed in the sacerdotal prayers of Jesus with the Father, as well as the resurrection and ascension Scriptures leading us to the Holy Spirit (the Paraclete), we open into the Trinity.
Sometimes it seems obvious, from comprehending from the inside out, but it is not obvious to others...not yet. But surely now it is. We may be able to grasp how easy it is to fragment Jesus, to diminish His Real Presence when we do not elevate our bodies, minds, hearts and spirits to the fullness of the Mass, all the Sacraments, as evidenced in each of the Three Persons of the Most Holy Trinity. St. John of Avila writes of this in sermons.
Teresa of Avila developed intimate friendship with the Blessed Trinity, as do all the saints, to my knowledge and that of various scholars and writers of the mystical life who elucidate the understanding that comes in love, in balance, of each Person as One: Triune God. "Now she [St. Teresa] realizes the full truth of the promise made by Our Lord, 'If any man love me, He wil keep my word and the Father will love him and We will come and make Our abode in him' (Jn 14, 23.)
St. Teresa herself writes:
"...by means of an intellectual vision, in which by representation of the truth in a particular way, the Most Blessed Trinity reveals itself in all three Persons. First of all the spirit becomes enkindled and illumined as it were by a cloud of the greatest brightness. It sees these three Persons individually, and yet by a wonderful kind of knowledge that is given to it, the soul realizes that most certainly and truly these three Persons are one substance and one Power and one Knowledge and One God Alone, so that what we hold by faith the soul may be said to grasp by sight, although nothing is seen by the eyes, either of the body or of the soul, for it is no imaginary vision. Here All Three Persons Communicate Themselves to the soul and speak to the soul and explain to it those words which the Gospel attributes to the Lord, namely that He and the Father and the Holy Ghost will come to dwell with the soul which loves Him and Keeps His Commandments" (Interior Castle, VII, ch. VII, p. 331).
From the inside looking out during Mass, this is what I have learned and know: We must elevate our love and devotion of His Real Presence as realized in all the Holy Sacraments in which the Holy Trinity is in All and All in One, although distinct Persons as well. All Sacraments are within the Mass; His Real Presence is the Holy Trinity as Each are One and Abide One with Another--and desire us to abide in Him and in Them, as One Body. We must not fragment any One Person of the Trinity, nor emphasize one over the other, no matter how tempting this may be due to trends in society and ecclesial groups, even in the Church.
Regardless, His Real Presence has chosen for this soul, for now to continue in this imperfect state during Mass, as ecstasy is only part of spiritual betrothal and is not spiritual matrimony. But it is teaching this soul much about its weaknesses as well as giving the soul much to pray about and to learn of others, of His Real Presence as the Holy Trinity in each Person and as One, and the desire of His Real Presence to draw each of our souls individually and as part of the Body, to Himself forever.
God bless His Real Presence in you! All peace on earth!