The Holy Spirit is a person, not an impersonal force. He speaks, leads, warns, decrees, teaches, chooses, calls and sends. He is given to the disciple to consecrate him as a prophet of the new era in Jesus Christ and to enable him to give witness to Christ as the particular circumstances and the will of God require.
John the Baptist, Elizabeth, Zachary and Simeon were all filled with the Spirit to give witness to the one who had come, Jesus the Messiah. In their different ways, they announced that the Saviour was here. The apostles, Stephen, Philip, Paul, Cornelius, and Barnabas, received the same grace of the Holy Spirit to carry out the same task of announcing Christ, though in different ways. The Holy Spirit filled our Lord with joy, descended upon Him and anointed Him in His humanity at the beginning of his public ministry.
We receive the anointing of the Holy Spirit at our Confirmation. It is a gift for which we should renew our thanks and devotion every year on the feast of Pentecost, resolving to be true to the vocation that we are given to be missionary disciples of Christ.