Father told us the idea of the Pentecostal Spirit, with the apostles being in the upper room, and the Holy Spirit decends upon them, empowering them and embolding them. They are no longer afraid, so they come downstairs and begin proclaiming the Good News. They could not help but preach that Jesus Christ is Lord. This is what the 2nd reading says, that no one can say Jesus is Lord, except by the Holy Spirit. Today, we might say this with ease, but then, it would be dangerous to say that because the only Lord then was Caesar, and one might suffer the death of a martyr.