Gevurot 20:7

Orthodox Jewish Bible

⁷ And on Yom Rishon, when we met for tish (it was Motzoei Shabbos when there was a Melaveh Malkeh communal meal), Rav Sha’ul was saying a shiur to them, since he would have to depart early the next day and was having to extend the message until chatzot halailah.