Sometimes a pshat hinges on reading a single word in a way that you never thought of before. A great example in the Netziv's interpretation of the burning bush (3:1-3). He raises two difficulties with the text. First, the nitpicky one: "Ha'sneh ainenu ukal" -- why does the pasuk say "ukal" instead of "ne'echal?" Second, the more striking one: we are told that the bush was "bo'er ba'eish," but then we are told that Moshe went to see "madu'a LO yiv'ar ha'sneh." Was it "bo'er" or was it not "bo'er?!"
We won't get to Parshas Mishpatim for a few weeks, but maybe you remember the source for the nezek of shein from Bava Kama: "Ki yaveir ish sadeh or kerem v'shilach es b'iro u'bi'er b'sdeh acheir..." (22:4) The pasuk there is talking about an animal that grazes is someone else's field and consumes the what is growing there. We see the word "bo'er" doesn't just mean to light on fire and burn -- it can also mean to swallow up and consume.
The Netziv ingeniously suggests that what Moshe saw was a bush that was "bo'er ba'eish," that was consuming, i.e. extinguishing the fire that was burning within it. It was the reverse of the natural order. Normally, it's the fire that consumes the wood as it burns -- here, the wood was consuming the fire.
Maybe, thought Moshe, the fire was simply running out of fuel and that's why it was going out. But no! "Ha'sneh ainenu u'kal," the wood was not consumed, i.e. there was still fuel for the fire. How could it be, wondered Moshe, that "lo yiva'ar ha'sneh," that the fire was dying out without it having consumed the remaining fuel wood of the rest of the bush? How could it be that the decrees of the Egyptians would diminish and eventually go out while there was still a Jewish nation left for the Egyptian to oppress? That, of course, is the question Hashem would answer in the following pesukim.