Now

This word is used here to mark a break in the main storyline. Here Matthew starts to tell a new part of the story.

so that they

Here "they" refers to the chief priests and the members of the council.

"might have a reason to execute him"

"two men came forward" or "two witnesses came forward"

If your language does not allow quotes within quotes you can rewrite it as a single quote. AT: "This man said that he is able to destroy ... days" (See: rc://en/ta/man/translate/writing-quotations and rc://en/ta/man/translate/figs-quotations)

"This man Jesus said"