I believe it's a sin for a born again Christian to spend any of his money that he earned to waste it on any form of gambling, including the lottery.
Off hand, I can't say that there's a specific verse that states that "Thou shalt not buy a lottery ticket," I see this as a matter of stewardship of the money that God gives us to get wealth.
In the OT economy, which was primarily an agrarian type of economy, a man's material wealth was primarily determined by the size of his flocks as in Job 1:1-3; in fact this very passage tells us that Job was the richest man of his day in the region of Uz. Nowhere do you find Job participating in any form of what today we'd call gambling in order to get rich quick--something which is roundly condemned throughout Proverbs.
In Deuteronomy 8:18 we're told that it's the LORD thy God that gives us the ability to get wealth. Why would God say that gambling in order to get wealth is okay when His word condemns gambling?
Proverbs 10:22a reads, "The blessing of the LORD makes a person rich." If it's God who gives us the ability to get rich, not gambling, do you really suppose He'd approve of gambling when His very Word condemns gambling?
Jesus Christ Himself in Matthew 25:14-30 gives us the parable of the unwise steward. Jesus condemned this unwise steward because the money that the man who was about to travel to a far country--which is symbolic of Christ returning to heaven and then coming back again at the Judgment Seat of Christ where His servants [We who are born again.] are judged according to what we did with the money He gave us--condemns His unfaithful servant because rather than using his money to make more money.
He told the unwise steward that, if nothing else, he should have at least deposited that money in the bank where it'd gain at least some interest on the steward's deposit.
The other servants were praised because they put the money that He gave them to work. As a result, Jesus praised the faithful stewards (Matt. 25:21 & 23) by telling them that they were faithful in a few things so now He's going to allow them to "enter into the joy of thy lord."
Notice that the wise stewards were praised for investing the money He gave them in that both of them, not for gambling with it--something that usually the only ones that gain any money are the ones that own the casinos.
Again, I seriously doubt Jesus will one day praise us for gambling with the money He allowed us to gain rather than making wise investments to order to increase that amount of money--some of which we can then give to our local church or to some other worthwhile Christian ministry that He may put on our hearts to donate in order that His Word may go forth to this lost and dying world.
