"Since the Torah does not mention it, rabbis had to write a responsum on whether or not it was okay for a flag of Israel to be on the bima."

"Responsa literature has its roots in the Geonic period (8 th century), and it continues to be written to this very day. By the year 2000, over 5,600 volumes - comprising over half a million rabbinic responsa - had been published." (source)