gambling the betting or staking of something of value, with consciousness of risk and hope of gain, on the outcome of a game, a contest, or an uncertain event whose result may be determined by chance or accident or have an unexpected result by reason of the bettor's miscalculation. (Brittanica, 1997)

In the Bible gambling is not specifically forbidden or condemned, but it is always associated with other sins, oppression, selfishness and bad motives. It has traditionally been identified as a vice -- because it is one.

Job 6:27 You would even cast lots for the fatherless and barter away your friend. (NIV)

Joel 3:3 They cast lots for my people and traded boys for prostitutes; they sold girls for wine that they might drink. (NIV)

Obad 1:11 On the day you stood aloof while strangers carried off his wealth and foreigners entered his gates and cast lots for Jerusalem, you were like one of them. (NIV)

Ps 22:18 They divide my garments among them and cast lots for my clothing. (NIV)
John 19:24 "Let's not tear it," they said to one another. "Let's decide by lot who will get it." This happened that the scripture might be fulfilled which said, "They divided my garments among them and cast lots for my clothing." So this is what the soldiers did. (NIV)
Mark 15:24 And they crucified him. Dividing up his clothes, they cast lots to see what each would get. (NIV)

Judg 14:12-13 "Let me tell you a riddle," Samson said to them. "If you can give me the answer within the seven days of the feast, I will give you thirty linen garments and thirty sets of clothes. If you can't tell me the answer, you must give me thirty linen garments and thirty sets of clothes." "Tell us your riddle," they said. "Let's hear it." (NIV)
Judg 14:15 On the fourth day, they said to Samson's wife, "Coax your husband into explaining the riddle for us, or we will burn you and your father's household to death. Did you invite us here to rob us?" (NIV)

Judg 11:30-31 And Jephthah made a vow to the LORD: "If you give the Ammonites into my hands, whatever comes out of the door of my house to meet me when I return in triumph from the Ammonites will be the LORD's, and I will sacrifice it as a burnt offering." (NIV)

The Bible does condemn the pursuit of "luck" or fortune or destiny, which are false gods.

Isa 65:11-12 "But as for you who forsake the LORD and forget my holy mountain, who spread a table for Fortune and fill bowls of mixed wine for Destiny, I will destine you for the sword, and you will all bend down for the slaughter; for I called but you did not answer, I spoke but you did not listen. You did evil in my sight and chose what displeases me." (NIV)

The previous passages made clear that it is usually the poor who are most victimized by gambling. The greed and selfishness is condemned repeatedly in scripture. Gambling, competing for that which belongs to someone else, is inherently covetous and contrary to love.

Ps 10:2-3 In his arrogance the wicked man hunts down the weak, who are caught in the schemes he devises. He boasts of the cravings of his heart; he blesses the greedy and reviles the LORD. (NIV)

Amos 8:6 buying the poor with silver and the needy for a pair of sandals, selling even the sweepings with the wheat. (NIV)

Exod 20:17 "You shall not covet your neighbor's house. You shall not covet your neighbor's wife, or his manservant or maidservant, his ox or donkey, or anything that belongs to your neighbor." (NIV)

Lev 19:18 "`Do not seek revenge or bear a grudge against one of your people, but love your neighbor as yourself. I am the LORD. (NIV)

1 Cor 6:8 Instead, you yourselves cheat and do wrong, and you do this to your brothers. (NIV)