Ибо не знал, что сказать; потому что они были в страхе.
(He did not know what to say, they were so frightened.)
For he did not know what to say, for they were terrified.
For he did not know what to answer; for they became terrified.
He said this because he didn’t really know what else to say, for they were all terrified.
For he wist not what to say; for they were sore afraid.
because he did not know what to say, for they were greatly afraid.
For he knew not what he should say, for they were filled with fear.