So it looks like the synoptic texts say “this generation” (see below KJV). Does anyone know where it is downgraded to “some of this generation” and then later to “who knows?”
Mark 13
29 So ye in like manner, when ye shall see these things come to pass, know that it is nigh, even at the doors.
30 Verily I say unto you, that this generation shall not pass, till all these things be done.
31 Heaven and earth shall pass away: but my words shall not pass away.
32 ¶But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father.
33 Take ye heed, watch and pray: for ye know not when the time is.
Matthew 24
32 Now learn a parable of the fig tree; When his branch is yet tender, and putteth forth leaves, ye know that summer is nigh:
33 So likewise ye, when ye shall see all these things, know that it is near, even at the doors.
34 Verily I say unto you, This generation shall not pass, till all these things be fulfilled.
35 Heaven and earth shall pass away, but my words shall not pass away.
36 ¶But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only.
37 But as the days of Noe were, so shall also the coming of the Son of man be.
Luke 21
31 So likewise ye, when ye see these things come to pass, know ye that the kingdom of God is nigh at hand.
32 Verily I say unto you, This generation shall not pass away, till all be fulfilled.
33 Heaven and earth shall pass away: but my words shall not pass away.