St Augustine the great African Bishop taught that we can think of the Blessed Trinity as the Lover, the Beloved and the Love itself.
The Father is the lover who gives himself completely to the Son, the Son is the beloved, the perfect recipient and response to the Father's love and the Holy Spirit is the bond of their love, or the eternal communion of Father and Son. But that eternal Divine Love overflows, that love between Father and Son reveals the love and is poured out as a loving gift. St Augustine gives another example of what it is like (not the same as - but like), the love between husband and wife bears fruit in a child. That child is their child it can only be understood as the fruit of the love of both mother and father and the child reveals, makes known, the love of father and mother.
As the gift of divine love the Holy Spirit is the gift of God, the Holy Spirit is God, and by the gift of the Holy Spirit we are brought into the mystery of the Divine life, the mystery of the Divine Lover, the Divine Beloved and the Divine Love between them. We can even say the Holy Spirit is the Giver, the Gift and the one who makes accepting the Gift possible. God wants to give us Himself, God gives us himself, and God makes it possible for us to receive this gift.
The Holy Spirit is light the light which enables us to see what God is offerring us, the light which enables us to see God, the light which is God.
Whilst Jesus was on earth, from the annunciation to his resurrection the Holy Spirit is seen as active. The Spirit overshadows Mary, Jesus is driven into the wildernesses by the spirit, especially in St John's gospel it is the Spirit who reveals the Father's will to Jesus and Jesus obeys - a loving obedience which leads him to the cross, on the cross it is the Holy Spirit who preserves the bond of love between the Father and the Son, even at the great moment of separation when the Father surrenders the Son into the hands of men and the Son experiences being forsaken by the Father.
Yet with the resurrection, as we have seen throughout Eastertide in the gospel, and after his ascension, culminating now in this feast of Pentecost Jesus in a sense resumes his active role, He pours out the Holy Spirit on his apostles and on the church. In the gospel the risen Lord says: receive the Holy Spirit, receive the divine love which is the fruit and gift of the love the Father has for the Son and which the Son receives with such joy, receive the love which I by my life, death, and resurrection have made known to you and thus become yourselves dispensers of divine forgiveness. In the acts of the apostles it is the descent of divine love which empowers the apostles to make known to the world the marvels of God, the divine mystery revealed by Jesus and in the epistle St Paul reminds us that it is the gift of divine love which makes it possible for us to recognise Jesus, and through baptism this gift unites us in the church the one body of Christ.
We should not lose this understanding of the Holy Spirit as the gift of divine love, which like light is necessary if we are to see. The organisation of the church, its division into bishops and priests and lay people, its traditions, practises, beliefs are of vital importance but at the same time the church and each of us must be caught up in that gift of divine love which is the Holy Spirit.