Matthew 23:39

γὰρ explains ἔρημος of Matthew 23:38. The Temple is desolate, for Christ, who is the Lord of the Temple, leaves it for ever.

ἕως ἂν εἴπητε. Till, like the children in these Temple-courts, ye recognise Me as the Messiah. See ch. Matthew 21:15. The words of Jesus, and the place, and the anger of the Scribes, may have recalled to some the scene in which Jeremiah, on the same spot, denounced the sin of Israel, called them to repentance, and foretold the destruction of the Temple: ‘then will I make this house like Shiloh’ … ‘and all the people took him, saying, Thou shalt surely die,’ Jeremiah 26:1-8.