The titles given to the Holy Spirit must surely stir the soul of anyone who hears them, and make him realize 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. To the Spirit all creatures turn in their need for sanctification; all living things seek him according to their ability. His breath empowers each to achieve its own natural end. 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. By nature the Spirit is beyond the reach of our mind, but we can know him by his goodness. The power of the Spirit fills the whole universe, but he gives himself only to those who are worthy, acting in each according to the measure of his faith.