Acts 22:9

and were afraid These words are omitted in the oldest MSS. and have been left out in the Rev. Ver.But they are not like anything in the other two accounts, the one of which (Acts 9:7) describes Saul's companions as being "speechless," the other (Acts 26:14) as "all falling to the ground." Therefore it seems best to retain them, as not being due to any annotation, or to the assimilation of one form of the story to another. The last three letters of this phrase are the same as those of the phrase preceding it, and the eye of a scribe in early times may have passed from one to the other, and thus words belonging to the earliest form of the narrative may have been omitted.

heard not the voice i.e. the words which were spoken to Saul. They were only conscious of a sound around them. See above on Acts 22:7.