For the law was given by Moses, but grace and truth came by Jesus Christ. John 1:17
I am, by nature, a messy person. I lose things all the time. But I have something that bails me out. I have my file cabinet. Now everything won't fit in there, but it really helps me find the important things.
If someone were to say, "I'll bet your cabinet is full of things you've invented," I would have to tell them, "Not one thing in there is something that I have invented. But I have a lot of things that someone else has invented in there."
This is what the Dispensational system is--a filing system. Not very exciting is it? But it keeps things straight. So when someone talks about the evil dispensations that someone has invented, I say. "He made them. We just file them to keep them straight." I challenge anyone to find a doctrine that we have invented.
The above scripture is a dispensation illustrated. It shows the change from Moses to Christ--from the Old Testament to the New. It is when we fail to make these distinctions that we can get into trouble.
Some tell us we are under the Law. To them I will say, "Do you eat bacon?". Maybe I'll say it to a vegetarian some day. Then I'll be in trouble.
Some say we are Israel, or that Israel was in the church. I have heard both. To these people I say, "You really need to work on your filing system."