"Then Agrippa said to Paul, 'Do you think that in such a short time you can persuade me to be a Christian?' Paul replied, 'Short time or long - I pray God that not only you but all who are listening to me today may become what I am, except for these chains.'" NIV translation
Evidently the Holy Spirit was working on Agrippa as he asked Paul about his motives for speaking. It is interesting to note that Paul told him that his goal was for all who heard his testimony to come to faith in Jesus Christ. That should be our goal as well and the reason that we share our testimonies.
The king rose, and with him the governor and Bernice and those sitting with them. They left the room, and while talking with one another, they said, 'This man is not doing anything that deserves death or imprisonment.' Agrippa said to Festus, 'This man could have been set free if he had not appealed to Caesar.'" NIV translation
Paul gave his testimony and completed his purpose there. It was clear to everyone that he was not guilty of anything but he was to be sent on to Rome. This is the same thing that happened to Jesus, in that, everyone could see that He was innocent and yet they crucified Him.