I don't think "responsible" gambling is a sin; however, it has the potential of being "irresponsible" gambling that would then become a sin when it robs your financial resources and relationships. Drinking alcohol is not a sin, but getting drunk is. I guess one could say gambling at excess (meaning the irresponsibility of surpassing the point where one isn't able to support himself or his family, pay bills, etc.) is a sin. In other words, if it causes you to be irresponsible with your relationship with God, managing finances, or established relationships, then it is sin.
My family and I, for a couple times per summer (although it's been a few years due to the economy), would go watch thoroughbred racing. We would set aside a specific amount of money based on the number of races for that day and not spend a penny more (usually $72-$80 altogether). We had pre-planned it, and my father would double-check finances to make sure it was okay to go. Some of those days we lost money, and other days we won money (I once won $82 at 40-1 odds through a $2 bet
). It would also be a good bonding experience between me my family.
If one gambles, it must be his servant, not his master. Cf. Matthew 6:24
