As We Look Toward Pentecost...

"The titles given to the Holy Spirit must surely stir the soul of anyone who hears them, and make him realise that they speak of nothing less than the supreme Being. Is He not called the Spirit of God, the Spirit of truth who proceeds from the Father, the steadfast Spirit, the guiding Spirit? But His principal and most personal title is the Holy Spirit... The Spirit is the source of holiness, a spiritual light, and He offers His own light to every mind to help it in its search for truth... The Spirit raises our hearts to heaven, guides the steps of the weak, and brings to perfection those who are making progress. He enlightens those who have been cleansed from every stain of sin and makes them spiritual by communion with Himself."

From Saint Basil's treatise On the Holy Spirit (Office of Readings)