Augustine (354-430) wrote this beautiful prayer to the Holy Spirit:

Breathe 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.