As he journeyed he came near Damascus, and suddenly a light shone around him from heaven.   Then he fell to the ground, and heard a voice saying to him, “Saul, Saul, why are you persecuting Me?”  

And he said, “Who are You, Lord?” 

Then the Lord said, “I am Jesus, whom you are persecuting.”

Acts 9:3-4   (NKJV)