The Holy Spirit is the third person of the Holy Trinity. Before Jesus ascended to heaven, he promised to send the Holy Spirit to his disciples to guide and teach them. The Holy Spirit acts as a consoler and advocate. Some key roles of the Holy Spirit include inspiring prophets of the Old Testament, anointing Jesus at his baptism, and descending upon the Apostles at Pentecost. The Holy Spirit sanctifies believers, grants the theological and cardinal virtues, and works through the sacraments and Church to bring all people into communion with God.