Two allegories teach Jerusalem’s ripeness for judgment. Ezekiel 15-16.
Jerusalem, the useless wood of a wild vine, Israel has no superiority over the nations to save it from destruction. Ezekiel 15:1-8.
Using three allegories, God foretells Judah’s imminent destruction. The first allegory shows Judah as a useless vine to be burned. The second is a vitriolic attack against Judah’s unfaithfulness, portraying Judah as an adulterous wife, worse than her two sisters, Israel and Edom, and less moral than a prostitute. The third allegory, using two eagles and a vine, calls specific attention to the personal ruin of King Zedekiah.
Note that the emphasis of the example is on the wood rather than the fruit. He is not asking what use is the vine, but of what use is the wood of the vine. Nothing is made from it. Not even a peg to hang a jug or picture on. It is useless. That is before it is burned. So how much more useless will it be after it has been burned. The fire consuming both ends, and the middle signifies that it is totally burned.
This is now applied to Jerusalem. She is the wood of the vine. The inhabitants of Jerusalem will be put through the fire – judgement, destruction.
In verse 7 some have escaped from the fire and yet they will be put through the fire. This is probably referring to the 597 B.C. fire from which they had escaped.
The present inhabitants of Jerusalem had come through that, but they are being told there is going to be a 586 B.C. fire which they will not escape from.