#Now Jacob

"Now" is used here to mark a change from the story to background information about Jacob. (See: [[:en:ta:vol2:translate:writing_background]])

#Jacob heard that he

The word "he" refers to Shechem.

#he had defiled

This means that Shechem had very much dishonored and disgraced Dinah by forcing her to sleep with him.

#held his peace

This is a way of saying that Jacob did not say or do anything about the matter. (See: [[:en:ta:vol1:translate:figs_idiom]])