en_tn_lite_do_not_use/luk/09/36.md

They kept silent ... what they had seen

This is information that tells what happened after the story as a result of the events in the story itself. (See: rc://en/ta/man/jit/writing-endofstory)

kept silent ... told no one

The first phrase refers to their immediate response, and the second refers to what they did in the following days.