The Holy Spirit (also known as the Holy Ghost) is the third person of the Trinity. It was the Holy Spirit that inspired the Old Testament prophets and the New Testament apostles. Most churches of Western Christianity affirm that the Holy Spirit proceeds from both God the Father and God the Son. Most churches of Eastern Christianity affirm that the Holy Spirit proceeds from God the Father alone. This doctrinal difference is one of the factors that led to the Great Schism.
According to Paul, among the fruits of the Holy Spirit are love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control (Galatians 5:22-23).