Mark 9:6

For he knew not what to answer; for they became sore afraid.

This is a classical example of Mark's use of "for" as a connective device for his narrative; and it should be noted that these two examples of it come right in the midst of a similar string of "ands" in the same paragraph. This is warning enough that these characteristic connectives in Mark cannot be made the basis of construing independent maxims as necessarily having any connection in thought or meaning.