The Holy Spirit is thus described as the Breath of God.
In the Bible we first meet the Holy Spirit at the beginning of creation. "In the beginning God made heaven and earth. The earth was a formless mass, and darkness covered the abyss, and the Breath of [God] brooded over the deep." (Genesis 1)
This same metaphor is used in the Gospel of St. John in describing how the Risen Jesus imparted the Holy Spirit upon his apostles: "He breathed on them and said, Receive the Holy Spirit: whose sins you shall forgive they are forgiven, whose sins you shall retain, they are retained." (John 20.22)
Breath is something gentle. But at Pentecost the Holy Spirit used a more violent symbol: He came to the apostles like a strong wind, like a typhoon. Also like tongues of fire. The fearful men cowering behind closed doors thus became enlightened and emboldened, unafraid to peach the Gospel even in the face of hostility.
A different symbol is used in Christian liturgy. The Holy Spirit is compared to oil, to a sweet soothing ointment – a healing presence. Thus oil and chrism are used in the sacraments of baptism, of Holy Orders, and in the anointing of the sick. A liturgical song calls Him "the sweet anointing from above" (spiritalis unctio).
Dante however uses a totally different metaphor for the Holy Spirit. In the Paradiso, the Pilgrim is finally admitted to the vision of the Trinity. And he exclaims:
O luce eterna che sola in te sidi,
sola t’intendi, e da te inteletta
ed intendente te, ami ed arridi.
"O eternal Light who alone exists by thyself; who alone knows thyself; and being known by thee and knowing thyself, you love and you smile."
In those three lines Dante has summarized the theological treatise on the Trinity: God is the only Being that exists without cause. Being infinite he alone knows himself. In doing so, he begets the Word, a perfect image of himself. Thus knowing and being known, God loves and smiles. The smile is the Holy Spirit.
St. Paul tells us that we are temples of the Holy Spirit. (1 Cor. 3.16). The Holy Spirit dwells within us. How wonderful to think (with Dante) that as God dwells in us, He loves us and He smiles.