Matthew 23:39

ἀπʼ ἄρτι, from this moment, Christ's prophetic work done now: it remains only to die. ἕως ἂν εἴπητε : a future contingency on which it depends whether they shall ever see Him again (Weiss in Meyer). He will not trouble them any more till their mood change and they be ready to receive Him with a Messianic salutation.

The exquisite finish of this discourse, in the case of ordinary orators, would suggest premeditation and even writing. We have no means of knowing to what extent Jesus had considered beforehand what He was to say on this momentous occasion. The references to the whited sepulchres and the tombs of the prophets show that the speech was in part at least an extempore utterance.