The highest expression of the spirit is the one that opens us to the Great Other, in love and trust. It establishes a dialogue with God, listens from the conscience to God’s call, and delivers us trustingly into the palm of God’s hand. This communion can be so intense, say the mystics of every tradition, that the soul of the beloved is fused with the Lover in an experience of nonduality; by grace we participate in God’s very being. Here the human spirit is touching the hem of the Holy Spirit’s garment.
—Leonardo Boff in Come Holy Spirit


We are all parts of one body, we have the same Spirit, and we have all been called to the same glorious future. For us there is only one Lord, one faith, one baptism, and we all have the same God and Father who is over us all and in us all, and living through every part of us. However, Christ has given each of us special abilities—whatever he wants us to have out of his rich storehouse of gifts.
— Ephesians 4:4-7


This love has as its object God, as well as other people. Christian theological tradition has most often seen the Holy Spirit in the Trinity as the bond of love between the Father and the Son. . . . The primary effect of the Spirit acting in people . . . will be love, both for one another and for God. . . .
God’s Spirit joins our spirit; it does not replace it. The good acts we perform are truly our acts, not simply acts of the Holy Spirit in us. The deepest part of the self is the spiritual dimension. From the center flows all our freedom and love; at this level we remain free to choose to move or not to move with the Spirit. The Holy Spirit is indeed active in us at all times drawing us toward greater love and service of God and others, but the Spirit does not control our response. That flows from our freedom.
—Richard Hauser in In His Spirit


…it is to a practical mysticism that the practical man is here invited: to a training of his latent faculties, a bracing and brightening of his languid consciousness, an emancipation from the fetters of appearance, a turning of his attention to new levels of the world. Thus he may become aware of the universe which the spiritual artist is always trying to disclose to the race… [This] is a natural human activity, no more involving the great powers and sublime experiences of the mystical saints and philosophers than the ordinary enjoyment of music involves the special creative powers of the great musician. As the beautiful does not exist for the artist and poet alone–so the world of Reality exists for all; and all may participate in it, unite with it, according to their measure and to the strength and purity of their desire… Mysticism is the art of union with Reality.
—Evelyn Underhill in Practical Mysticism: A Little Book for Normal People


While outer knowledge can be easily acquired, inner truth demands an absolute concentration of the mind on its object. So in the third stage of samadhi or identification, the conscious division and separation of the self from the divine being, the object from the subject, which is the normal condition of unregenerate humanity, is broken down. The individual surrenders to the object and is absorbed by it. He becomes what he beholds. The distinction between subject and object disappears. Tasting nothing, comprehending nothing in particular, holding itself in emptiness, the soul finds itself as having all. A lightning flash, a sudden flame of incandescence, throws a momentary but eternal gleam on life in time. A strange quietness enters the soul; a great peace invades its being. The vision, the spark, the supreme moment of unification or conscious realization, sets the whole being ablaze with perfect purpose. The supreme awareness, the intimately felt presence, brings with it a rapture beyond joy, a knowledge beyond reason, a sensation more intense than that of life itself, infinite in peace and harmony.
When it occurs our rigidity breaks, ‘we flow again, and—are aware, as at no other time, of a continuity in ourselves—and know more than the little section of it that is our life in this world! When we find the real in our own heart, we feel exalted and humbled. The memory of the eternal illumination has enduring effects and calls for renewal. Plotinus gives a glowing description of this state.
‘Since in the vision there were not two things, but seer and seen were one, if a man could preserve the memory of what he was when he was mingled with the divine, he would have in himself an image of God. For he was then one with God, and retained no difference, either in relation to himself or to others. Nothing stirred within him, neither anger nor concupiscence nor even reason or spiritual perception or his own personality, if we may say so. Caught up in an ecstasy, tranquil and alone with God, he enjoyed an imperturbable calm, shut up in his proper essence he declined not to either side, he turned not even to himself; he was in a state of perfect stability; he had become stability itself. . . . Perhaps we ought not to speak of vision; it is rather another mode of seeing, an ecstasy and simplification, an abandonment of oneself, a desire for immediate contact, a stability, a deep intention to unite oneself with what is to be seen in the sanctuary.’
—Sarvepalli Radhakrishnan in Eastern Religions and Western Thought