What do you think of casting lots to determine God's will?
I think it's a bad idea, almost always.
It's a bad idea because, when you read the whole New Testament, the normal way over and over and over again for discerning the will of God is not casting lots but "being transformed in the renewal of your mind that you may be able to prove what is the will of God, what is good, acceptable and perfect" (Romans 12:1-2). And you have Ephesians 5:17: "Strive to know what the will of the Lord is."
If it's as easy as just rolling a dice every time you've got a decision, then you've just got to get it down to two and roll the dice, or get it down to three and say, "Top three numbers!" But if it was that simple Paul just wouldn't have talked like that.
So the New Testament portrays discovering the will of God in other ways than lot casting.
Should you ever take your Bible and just flip it open and take the first text you see as your answer?
Example: "...who acquit the guilty for a bribe and deprive the innocent of his right" (Isaiah 5:23). So, don't give bribes? Yes, you shouldn't. But you shouldn't read it out of context. That's obviously an indictment of bribery, and you might not know that if you didn't read the rest.
I do not think it is wrong to just flop your Bible open anywhere and plead for something special for you. But it better mean what it says! I mean, you better get the meaning right, rather than the old joke, "Judas went out and hanged himself," and "Go thou, and do likewise" is the next text you look at. It's ridiculous.
But as far as rolling dice, that would be incredibly rare.
I'll give you an instance when we do it. We come to elder meetings and you have to have a certain quorum of lay elders to staff elders at Bethlehem. There are usually too many staff elders there. Which of them should not be allowed to vote?
We do it by lot. The chairman writes down three numbers, if three can vote. And we go around and chose numbers. And the numbers that get them, they're included. So, that's a little illustration.