A person may draw lots with his children and his family members at the table, and he may even do so with a large portion against a small portion. What is the reason for this? It is in accordance with the ruling that Rav Yehuda said that Rav said.
Rav Yehuda quoted Rav as saying that since all of the money really belongs to the head of the household, there is no problem using money as an educational device, and even lending money with interest is permitted within the family. The Gemara continues:
Although with one’s children and family members, yes, this is permitted, with others it is not. What is the reason for this? It is in accordance with the ruling that Rav Yehuda said that Shmuel said: Raffling a large portion against a small portion is prohibited to do for other people, even on a weekday. What is the reason? Due to the prohibition against gambling with dice, which is prohibited by rabbinic law as a form of theft.
Dice players, who are professional gamblers, are among the people that the Sages disqualified as witnesses. The Sages disagreed with regard to the rationale for this, with the Gemara in Massekhet Sanhedrin (daf 25) offering two explanations for this. Rami bar Ḥama taught that the problem with a dice player is one of asmakhta – when gambling, neither side thinks that he will lose which will lead to a situation where the winner takes the loser’s money against his will. Therefore, one who takes money in this fashion is considered a robber by rabbinic decree. Tosafot offer a somewhat similar explanation. Rav Sheshet, on the other hand, taught that the problem with a dice player is that he is eino osek be-yishuvo shel olam – that someone who makes his living by gambling is not involved in positive community activities. Thus, even according to those who say that money won through gambling is not considered stolen, gambling is nonetheless considered despicable behavior.