I saw the video over the word "generation" and how you David S explained it.
One thing for sure, is David doesn't understands at all how Hebrews sees and understands things.
Let me explain...
Middle Asians from antiquities, and Hebrews saw things, in a complete different way than Europeans are perceiving times and events!
We, as modern Europeans, we see the future in front of us, past in our back, right ?
.... for the Jews it s the contrary.
How come ?
Well, for a Jew they think past is in front of them because they can see it.
Future is in their back, as they can't see it.
Same thing for a generation.
Generation are seen from the perspective of the people who lived but died until a certain point, not the contrary as Europeans sees the generation from a date of birth.
Now really you can have a complete understanding of this when the Bible says :" the date of death worth more than the date of birth"....
Again, you can judge not from how a person was born, but from what he had done in his life, same will apply for a generation.
Also as the wt stated well that the things described by the "sign" of the parousia were chronological, and happening in a certain order, the verse that talks about the genea is located not directly in reference of the parousia, but in the text referring to the great tribulation. If you would have kept the same logic then it means those who will lived the great tribulation, will have known and understood what the sign was really about, and how intense things would become, as posteriori by living and experiencing this, just as a normal Hebrew could see and understand the things to come from what he will actually live.
As a matter of fact, 1st Christians who escaped and survived the events that took place in the 1st century and who would have believed in Jesus, would have a full understanding of it, by living it, just as you can taste a fruit, the fig by eating it, not by noticing it just suddenly appeared on the fig tree.
"By their fruits, you will recognize them", same simple thought here from Jesus, any child can understand that.
It s the same view from the Spirit has when He guided David to wrote :
“Sit at my right hand
Until I place your enemies as a stool for your feet.”
Even in Gen 1:1, this is not an human thing to start a story by telling the ends.. .
The perspective of the spirit, is not from JUST from its beginning when there was nothing, but by its plain fulfillment, like a cameraman filming the panorama of the whole CREATION, not only in the 1st day but as a whole in time also in space, with a focus on the results of all the beautiful creations from Elohim (The Great Creator) with the divine plan to accomplish the works of His hands, the physical Heavens with a special purpose towards the earth... who could weight how much efforts and energy was put in there just to accomplish this purpose of this very verse, if so much energy for the final touch of his finger, the humans. Now weight the love of God.