According to Jewish law, when a young woman is living at home and is supported by her father, any money that she earns belongs to her father. What is the halakha when the father has passed away and she is being supported by her brothers? Do they also deserve to receive her earnings? Our Gemara brings a teaching that clearly states that in such a case she keeps her earnings. The Gemara offers two possibilities on the author of this statement. It is either: Rav Zeira quoting Rav Mattana; or Rabbi Zeira quoting Rav Mattana.
What is the difference between these two traditions?
Generally speaking, the difference between the title “Rav” and “Rabbi” is whether or not the Sage in question has received semikha – formal ordination. Biblically, only those sages who receive formal ordination from their teachers can act as judges for all Torah laws, for they belong to a chain of tradition stretching back to the court of Moses. Towards the end of the second Temple period, this formal ordination was recognized by bestowing the title “Rabbi” on its recipients. The Gemara in Massekhet Sanhedrin teaches that semikha was only given in Israel, which meant that even great Sages who lived in Babylon were not properly ordained, and did not receive this title. They were simply called “Rav.”
Some Babylonian sages moved to Israel and retained the title “Rav,” while others did receive semikha in Israel. Of these, some arrived in Israel at a young age and their teachings are always quoted with the title “Rabbi” before their name; others had already made a name for themselves before receiving semikha, and while we find that some of their teachings are quoted in their name with the title “Rabbi,” others are still transmitted with the title “Rav.” Rabbi Zeira was one of these sages, and we find here an example of the Gemara trying to establish whether this particular teaching dated from his younger years as a Babylonian scholar, or his later years after he had already received semikha in Israel.