"I believe in the Holy Spirit, the Lord, the giver of life, who proceeds from the Father and the Son, who with the Father and the Son is adored and glorified, who has spoken through the prophets."
The Holy Spirit is the third of the three in the Trinity, part and one with God, often pictured as a dove or tongues of fire. Ancient pagan tradition taught that dove was a symbol of love, so when the Holy Spirit appeared to the early Christians, they understood that the Spirit was truly God's Love for them. The Spirit can and will fill men and women, giving them the insight to lift their voices for God, like the prophets in the Old Testament.
The Holy Spirit works through us in the Church, present in the sacraments of Baptism and Confirmation. The Spirit builds up the Church and provides us (the Church) with the gifts we need to continue to support our God's Church on earth. St. Augustine called the Spirit "the quiet guest of our soul," we have to be quiet and invite the Spirit in. Just as we ask for the Spirit to come to the child being baptized or to us during our Confirmation, in our every day lives, we can quiet our souls and ask for the Spirit's love and presence.
P.S. What about the Son? Look under Categories to your right!