Lesson 2 St. Patrick and the Trinity The Holy Trinity is God the Father, God the Son, and God the Holy Spirit. Catechism Connections Lesson Topics Holy Spirit Holy Trinity Sign of the Cross St. Patrick Essential Lessons Lesson Vocabulary Holy Spirit: The third Person of the Holy Trinity. He makes us holy and guides us to become more like Jesus. Trinity: The Trinity is the Christian mystery revealed to us by God that He is three Persons in One God: God the Father, God the Son, and God the Holy Spirit.