Here are some thoughts from different sources on the Third Person of the Blessed Trinity.
“The things no eye has seen, no ear has heard, things beyond the mind of man, all that God has prepared for those who love him: these are the very things that God has revealed to us through the Spirit, for the Spirit reaches the depths of everything, even the depths of God.”
I Corinthians 2: 9-10
Come down O Love Divine
Seek Thou this soul of mine
And visit it with Thine own ardour glowing;
O Comforter draw near,
Within my heart appear,
And kindle it, Thy holy flame bestowing.
O let it freely burn,
Till earthly passions turn
To dust and ashes in its heat consuming;
And let thy glorious light
Shine ever on my sight,
And clothe me round, the while my path illuming.
Let holy charity
Mine outward vesture be,
And lowliness become mine inner clothing;
True lowliness of heart,
Which takes the humbler part,
And o’er its own shortcomings weeps with loathing.
And so the yearning strong,
With which the soul will long,
Shall far outpass the power of human telling;
For none can guess its grace,
Till he become the place
Wherein the Holy Spirit makes his dwelling.
Bianco da Siena († 1434)
Transl. R F Littledale (1833-90)
“It is the Spirit of God who lifts up our hearts, takes the weak by the hand, makes perfect those progressing. He it is who shines on those whose hearts are purified and stainless and makes them truly spiritual through the common union they have with him. Just as a sunbeam, falling on light and transparent bodies, makes them exceedingly bright and causes them to pour forth a brilliance from themselves, so too souls which bear the Spirit and are illuminated by the Spirit become spiritual themselves and send forth grace to others. Hence comes to us foreknowledge of the future; understanding of mysteries; discernment of what is hidden; the sharing of good gifts; heavenly citizenship; a place in the choir of angels; joy without cease; abiding in God; likeness unto God; and, what is best of all, being made God.”
St Basil the Great, On the Holy Spirit, ch. 9, 22-23
“When the Spirit of God finds a soul in which He can work, He uses that soul for any number of purposes: opens out before its eyes a hundred new directions, multiplying its works and its opportunities for the apostolate far beyond the ordinary strength of a human being.”
Thomas Merton, The Seven Storey Mountain