The disciples were told to start preaching the Gospel in Jerusalem, which was the most difficult place for them but God gave them the power of the Holy Spirit, boldness to preach in the face of opposition and signs and wonders to confirm the message. The message was: You killed the Messiah but God raised Him from the dead and we are witnesses to His resurrection. These pious Jews had acted in ignorance and god gave them the first chance to repent of their sin and receive Christ. They did by the thousand but also there was much opposition from the religious authorities.
26th February 2017 am Andrew