Acts 9:1-19

As Saul was traveling to Damascus, he saw a blinding flash of light and heard the voice of Jesus asking why he was persecuting Him. Jesus then told him to go into Damascus and wait for further instructions. The Lord called on a believer in Damascus named Ananias to go to Saul and lay hands on him to restore his sight. Ananias knew of Saul's reputation and was hesitant to go, but the Lord assured him that Saul had been chosen to be a witness for Him.

God can use anyone. No matter what they've done in the past, God can take them and change them from the inside out to be used for His glory. Don't be too hasty in judging others. Some of the people that look least likely to accept God from our point of view are exactly the ones who need to hear about Him. Let God lead point you to the right people to witness to and make sure that your own feelings and presuppositions aren't getting in the way.