Talking about Christianity, it didn't only talk about greed of the love for money but it also condemned it in the bible when the gamblers were seen in the act of gambling and were chased away and that I think signifies those who desire to come close to God should avoid involving themselves in it. But these things don't work that way as more people in the Christendom find themselves gambling even publicly and this is because many feel they can make ends meet with gambling in this harsh economy.
It's quite possible; I haven't read the Bible, but I wouldn't be surprised if it explicitly mentioned that gambling is a sin. As I mentioned in my previous post, I'm an atheist and can't say I'm too bothered about what religion or the Bible says. It wouldn't affect me either way. However, if you take into account the Bible, a lot of things we do on a daily basis, or at least quite frequently, are considered sins. Thus, why should anyone take into consideration whether religion condemns gambling or not?