Gambling, for the most part, is permitted in Judaism.
Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
That there are no references to gambling in the Bible can hardly lead to the conclusion that this activity, found in all cultures both ancient and modern, was unknown in the biblical period; although it can be concluded that gambling was not widespread enough to constitute a social evil, otherwise its condemnation would have been recorded somewhere in the biblical records.
The casting of lots is mentioned not infrequently in the Bible but this has more to do with divination rather than with gambling proper. Lots were cast to determine which of the two goats were to be offered to God and which to Azazel (Leviticus 16: 810); in the affair of Jonathan (I Samuel 14: 423); and to divide up the land (Numbers 26: 55 and Joshua 15). Among non-Israelites, the sailors cast lots in order to determine who was responsible for the storm (Jonah I: 7) and Haman cast lots to determine the most suitable month in which to realize his plan to destroy the Jews (Esther 3: 7).
The famous German halakhist Jair Hayyim Bacharach (1639-1702) did, however, apply the biblical references to casting lots to gambling, even going so far as to conclude that a raffle is a legitimate means of allowing divine providence to operate in favor of the winner (Responsa, Havvot Yair, no. 61). Bacharach quotes in support the verse: "The lot is cast into the lap; but the whole disposing thereof is of the Lord" (Proverbs 16: 33).
From the legal point of view, the Mishnah (Rosh Ha-Shanah I: 8 and Sanhedrin 3: 3) states that two types of gamblers are untrustworthy and therefore disqualified from acting as witnesses in a Jewish court of law. These are the dice-player and, according to one opinion, the man who bets on pigeon-racing. The reason why the gambler is disqualified is discussed in the Talmud (Sanhedrin 24b).
One rabbi holds that it is only the gambler who has no other occupation, that is, the professional gambler who earns his living by gambling, who is disqualified and the reason is because he makes no useful contribution to society. Another rabbi holds that the disqualification applies even to the occasional gambler, even if he does have a useful occupation. According to this rabbi the gambler is disqualified because in betting, the one who bets believes that he is going to win so that there is no firm determination, as there is in other contractual obligations, by the loser to payout. The winner is disqualified because, by pocketing his winnings, he is a thief, taking that to which he has no legal entitlement.