Make it as sure as you can (asphalisasthe hōs oidate). “Make it secure for yourselves (ingressive aorist middle) as you know how.”
Have a guard (echete koustōdian), present imperative, a guard of Roman soldiers, not mere temple police. The Latin term koustodia occurs in an Oxyrhynchus papyrus of a.d. 22. “The curt permission to the Jews whom he despised is suitable in the mouth of the Roman official” (McNeile).