John Gill Commentary Ezekiel 13:14

"So will I break down the wall that ye have daubed with untempered [mortar], and bring it down to the ground, so that the foundation thereof shall be uncovered; and it shall fall, and ye shall be consumed in the midst thereof: and ye shall know that I am Jehovah." — Ezekiel 13:14 (ASV)

So will I break down the wall that you have daubed with
untempered [mortar]
Which is repeated and expressed in these words, both for the sake of confirmation and explanation of what is before said: and bring it down to the ground, so that the foundation thereof shall
be discovered ;
meaning the city of Jerusalem, and by these phrases declaring the utter destruction of it; whereby also would be discovered the vain assurances and lying predictions of the false prophets, and which would appear to be entirely groundless:

so the Targum, ``and I will destroy the city in which you have prophesied false prophecies; and I will cause it to fall to the ground, and its foundations shall be discovered:''

and it shall fall, and you shall be consumed in the midst of it ;
the false prophets perished in the destruction of Jerusalem, and not one of them escaped:

and you shall know that I [am] the Lord ;
who is true to his word, and able to accomplish it, whether of punishment or of threatening.