Good question. First, make sure you read our previous post on gambling. Our conclusion, based on biblical principle, is that gambling is wrong. That being said, what about investing? I believe there is a difference. Gambling entails risking money in hopes to make more money quickly. Investing involves the purchase of partial ownership in companies in hopes to make money over time. The latter is a sound means to plan for the future. Matthew 25:16-18 is a parable of wise investment, not gambling.
Of course, there are grey areas (e.g. What about day trading? What about the Poker player who is very good at what he does? etc.). The list can go on and on. Still, I believe there is a principle we can derive from Scripture that can help us distinguish between gambling and investing. The fundamental difference comes down to intent. Is what you are doing for the purpose of being a faithful steward of God's resources, or because you are dissatisfied with what God has given you? Are you satisfied in God or the need to accumulate more wealth? Are you trying to provide for your family or trying to enhance your own pleasure? (1 Tim. 6:17-18).
Being faithful with the resources God has generously given us could mean saving up for education, emergency or family planning. Proverbs 28:20 says this: "A faithful man will abound in blessings, but whoever hastens to be rich will not go unpunished." This verse speaks against gambling's "get rich quick" mentality. Trying to make lots of money overnight is not only unwise, but brings forth judgment. Investing as a long-term plan for the future, on the other hand, can be wise and fruitful - if your intent is God-centered.
[Answered by Pastor HM]