The Holy Spirit is now able to do the impossible. The Holy Spirit can produce a holy life in weak and sinful flesh. Let me illustrate this truth by using a very homely incident.
Suppose a housewife puts a roast in the oven right after breakfast because she is going to serve it for the noon meal. The telephone rings. It is Mrs. Joe Dokes on the phone. Mrs. Dokes begins with “Have you heard?” Well, the housewife hasn’t heard, but she would like to; so she pulls up a chair. (Someone has defined a woman as one who draws up a chair when answering a telephone.) Mrs. Dokes has a lot to tell, and about an hour goes by.
Finally our good housewife says, “Oh, Mrs. Dokes, you’ll have to excuse me. I smell the roast—its burning!” She hangs up the phone, rushes to the kitchen, and opens the oven. Then she gets a fork and puts it down in the roast to lift it up, but it won’t hold. She can’t lift it out. She tries again, closer to the bone, but still it won’t hold. So she gets a spatula. She puts the spatula under the roast and lifts it out. You see, what the fork could not do, in that it was weak through the flesh, the spatula is able to do. Now, there is nothing wrong with the fork—it was a good fork. But it couldn’t hold the flesh because something was wrong with the flesh—it was overcooked. The spatula does what the fork could not do.
The Law is like the fork in that it was weak through the flesh. It just won’t lift us up; it can’t lift us up. But a new principle is introduced: the Holy Spirit. What the Law could not do, the Holy Spirit is able to do. Therefore, you and I are to live the Christian life on this new principle. We are not to try to lift ourselves up by our own bootstraps. We’ll never make it that way, my friend. We make resolutions and say, “I’m going to do better”—all of us have said that. But did we ever do better? Didn’t we do the same old things?
God is able to do this new impossible thing by sending His very own Son, His own nature in the likeness of sinful flesh. Romans 8:4--Through The Bible Commentary, J. Vernon McGee