Mark 9:6

because he did not know what to say, since they were terrified.

For he did not know what to say, for they were terrified.

For he wist not what to say; for they were sore afraid.

For he did not know how to reply; for they became terrified.

(He did not know what to say, they were so frightened.)

because he did not know what to say, for they were greatly afraid.

He said this because he didn’t really know what else to say, for they were all terrified.

For he didn’t know what to say, for they were very afraid.