What did St. Catherine of Siena teach us about prayer?

Teresa's insights into prayer are unparalleled. It is not that she will tell us anything startling new. Understand that it is Christ alone who makes all things new and profound. Jesus through his Spirit is so startling because he is thoroughly ineffable, thrilling, and unutterable. When Teresa writes, we somehow begin to immediately feel comfortable and identify with her. It is through her spirit that and her communication and tone, and her conversational quality of prayer, that she describes, that draws us to her and God. God uses her to impart and inspire because she is a most holy and intriguing person and identifies with us and draws us to God intimately through God's holy and sacred Spirit. Teresa is contagiously inspirational.