John Gill Commentary Acts 22:9

"And they that were with me beheld indeed the light, but they heard not the voice of him that spake to me." — Acts 22:9 (ASV)

And they that were with me saw indeed the light
For it shone about them, as well as Saul:

and were afraid ;
the Alexandrian copy, the Vulgate Latin, and Syriac versions, have not this clause; but it stands in the Arabic and Ethiopic versions; the suddenness, greatness, and extraordinariness of the light surprised them, for it was even miraculous:

but they heard not the voice of him that spake to me :
they heard the voice of Saul, but not the voice of Christ; at least they did not hear it so as to understand it; (See Gill on Acts 9:7).