Warners are messengers who warn them. A reminder is established in the meaning of a warning. This is either because 'warn' and 'remind' are close in meaning, so it is as if it were said: 'reminders of a warning.' Or it is because it is an adjective of the pronoun in 'warners,' meaning they warn them who have a reminder. Or it is because it is an object for the purpose of meaning: they warn for the sake of admonition and reminder. Or it is raised as a subject of an omitted predicate, meaning: this is a reminder. The sentence is an interruption. Or it is an attribute meaning: warners who have a reminder. Or they made it a reminder due to their thoroughness in reminding and their elaboration in it. Another point is that 'reminder' could be related to 'We did not destroy' as an object for the purpose. The meaning is: and We did not destroy any of the people of a village who were wrongdoers except after We established the proof against them by sending warners to them, so that their destruction would be a reminder and lesson for others, so that they do not disobey like their disobedience. And We were not wrongdoers, so as to destroy a people who were not wrongdoers. This point is the one relied upon. If you say: how did you separate the 'and' from the sentence after 'except' and did not separate it in the saying 'And We did not destroy any village except that it had a known decree'? I say: the original is to separate the 'and' because the sentence is an attribute of the village, and if it is added, it is for the confirmation of the connection of the attribute with the described, as in the saying 'Seven and the eighth of them is his dog.'