That's my response to the previous post "What to do?" Speaking strictly for myself and not as pastor, I would take the $600,000 offering and put it WORK for the glory of God. The heart intent is God's greatest concern and clearly the giver in that story was trying to express his gratitude to God for the financial windfall. My thought is that I don't want to be the Pharisee who tells him God doesn't want his dirty money.
Furthermore, as someone noted in one of the comments, if we begin asking questions like that, do we have to keep asking them? Where did this money come from? How did you get it? Was it legal?
At the same time, it seems to me the Apostle Paul encountered this question in 1 Corinthians 8 dealing with meat sacrificed to idols. Paul employed what we now call "the weaker brother" principle meaning don't act in ways that might cause another to sin. With this in mind, I'm not sure what I would do. Would accepting the money be condoning the lottery? Perhaps we'll never to answer these questions, but, as Scripture says, "He who needs wisdom, let him ask of the Lord who gives richly."