A.T. Robertson Commentary Acts 9:13

"But Ananias answered, Lord, I have heard from many of this man, how much evil he did to thy saints at Jerusalem:" — Acts 9:13 (ASV)

How much evil (οσα κακα). How many evil things. Saul's reputation (26:10) as a persecutor had preceded him.

To thy saints (τοις αγιοις). Dative of disadvantage. "Used here for the first time as a name for the Christians" (Knowling), but it came to be the common and normal (Hackett) term for followers of Christ (9:32,41; 26:10; 1 Corinthians 1:2, etc.). This common word is from το αγος, religious awe or reverence and is applied to God's name (Luke 1:49), God's temple (Matthew 24:15), God's people as set apart for God (Luke 1:70; Luke 2:23; Romans 1:7, etc.). Ananias in his ignorance saw in Saul only the man with an evil reputation while Jesus saw in Saul the man transformed by grace to be a messenger of mercy.