Acts 4:31
"And when they had prayed, the place was shaken where they were assembled together; and they were all filled with the Holy Ghost, and they spake the word of God with boldness."
The boldness of the Apostles is clearly seen in this chapter as they preached about Jesus Christ. After the crowds heard their preaching, five thousand people accepted Christ as their Saviour. This troubled the religious leaders because they were quickly losing influence. This caused them to take Peter and John and hold them until they were questioned. Peter did not back down, but testified that Jesus was crucified by their hands, and that Jesus was the very One Who could save them from their sins. After being threatened and warned not to preach about Jesus, they were let go.