From Vatican News:
Pope Francis started off by reflecting on the courage shown by the Apostles when they were dragged before the Sanhedrin to stand trial for preaching the Good News of Jesus Christ (Acts 5:34-35,38,39).
He said they spoke with conviction and with one voice in the face of their accusers, who wanted to imprison them and halt the spread of the Gospel. “The Apostles become the ‘megaphone’ of the Holy Spirit, sent by the Risen One to spread quickly and unhesitatingly the Word that brings salvation,” he said. Pope Francis said these same men acted like “cowards” when Jesus faced similar circumstances. After Pentecost, however, they were completely changed and propelled onwards.