“As for these things that you see, the days will come when there will not be left here one stone upon another that will not be thrown down.”
See here, I. With what admiration some spoke of the external pomp and magnificence of the temple, and they were some of Christ's own disciples too; and they took notice of it to him how it was adorned with goodly stones and gifts, Luk 21:5.
Commenting on Luke 21:5-19
As for these things which ye behold,.... Some, as the Syriac and Ethiopic versions, read these words by way of interrogation; "are these the things which ye behold?" do ye look upon these with wonder and delight? the days will come; and they are hastening on; a little while, a few years more: in the which there shall not be left one stone upon another...
One stone upon another - This was literally fulfilled. See Mat 24:2.