Don't miss all the personal drama here! Let me break it down for you.
Saul/Paul - A converted Jewish Christian and former Christian persecutor
Ananias - A Christian highly respected by the Jews in Damascus
Angry Jewish Mob - Saul/Paul's ex-buddies
Paul is addressing a group of Jews from Jerusalem. More than likely there are some in the group that even knew Paul way back in his "Saul-ish" days. Those would be the days back when he was persecuting the Christians. He mentions Gamaliel, the high priest, and the Council can testify to his former life and his past "fervency" for the Jewish faith.Yet here he is now, facing the same sort of mob that he stood in approval of back during the stoning of Stephen.
Not only that, but he includes in his testimony the account Ananias, a Christian from Damascus. So the message that Ananias delivered to Paul (v.14-16) was probably a very emotionally charged message for Ananias to give to a very recent persecutor of the church.
So, in essence, Paul is relaying a message from an enemy who became a brother, to brothers who had become enemies.
And this can somtimes be our story as well. While we are called to "live at peace with all men as far as it depends on you", this is not always possible. You should decide today whom you will please, man or God. Decide whether you will risk offending the sensibilities of our culture, or offending the Ruler of the Universe. I know, it seems an easy decision the way I put it. But it never is when it comes right down to it.