This is the final installation of the series on Avot and Toldot. In this shiur we brought together the various sources that attempt to find a source for the number 39. We note that clear that the content of the 39 is clearly based on a mesora of the Oral Law. However, the number 39 itself may come from careful Rabbinic commentary. This shiur also gave us the opportunity to again discuss the broader question of what the concept of Avot teaches us in terms of the nature of Shabbat.
Here are the mekorot that we worked with (link).
And here is the audio: