'Fail' in the Bible

the Jews established and made a custom for themselves and for their descendants and for all those who allied themselves with them, so that they would not fail to celebrate these two days according to their regulation and according to their appointed time annually.

So these days were to be remembered and celebrated throughout every generation, every family, every province and every city; and these days of Purim were not to fail from among the Jews, or their memory fade from their descendants.