"Breath in me, O Holy Spirit, that my thoughts may all be holy. Act in me, O Holy Spirit, that my work, too, may be holy. Draw my heart, O Holy Spirit, that I love but what is holy. Strengthen me, O Holy Spirit, to defend all that is holy. Guard me, then, O Holy Spirit, that I always may be holy."  - St. Augustine 

We called him the Holy Spirit because one of his essential works in those who have been baptized is to sanctify them, to make them and keep them holy. When we were baptized, we became the adopted sons and daughters of God. God's own divine life pulsated within us. Throughout our lives, the Spirit sustains us in this life of God in different ways. He is working within us now, sustaining us in God's life. Just as we may not be conscious of the maintenance of our human life, we may not be conscious of the continuation of our shared life with God. It is the Holy  Spirit who accomplishes this in us. Give thanks to the Spirit for his personal care of us!  Do nothing to grieve the Holy Spirit, so that the life of God may remain in us. The above prayer may help to keep us attentive.