איסור גיורא

The prohibition of conversion, and he gave at the time of his passing before Rava to Rav Mari, his son, who was not then present, a sum of thirteen thousand zuz in acknowledgment, because a convert does not inherit from his father. [See Bava Batra (139a) regarding the prohibition of conversion, it was for him twelve thousand zuz in the house of Rava. Rav Mari, his son, was born not in holiness, and his birth was in holiness (for he had relations with Rachel, the daughter of Mar Shmuel, before he converted, and she became pregnant from him with Rav Mari, and in the meantime he converted, and Rav Mari was born from the daughters of Shmuel who were captured, as it is stated in Ketubot, Rashbam).

And in the house of Rava, Rava said: How can Rav Mari acquire these zuz through inheritance? Is he not a non-heir? If through a gift, the gift of a dying person is like an inheritance (therefore I acquire them, for the possessions of the convert are like hefker, and they are in my hands, and behold, I am prior and acquire). And he acknowledged the prohibition, for these coins of Rav Mari, his son, are his, as they taught him to do so, and Rava was particular, etc.

And in the Tosafot on Kiddushin (18a), it is questioned how Rava wished to acquire them, since his birth was in holiness]. In Avodah Zarah, chapter of the hired worker [(1a)], it was said to Rava when he was a non-Jew, he thought that a Jew does not observe the Sabbath, for if he found a purse of dinars, he would take it, and he did not know that he could not carry it less than four cubits. He conducted business with Rav Safra and they came before Rava, son of Rav Huna [(Baba Metzia 31b)] who was wise, and his sons and the sons of his sons were Amoraim [(see above, Rav Acha the elder)].