I see quite a bit of inquiry about the generation in Matthew 24:34, Mark 13:30 and Luke 21:32. In every scripture in the Gospels, the term generation is referring to a wicked generation except for Matthew 24:34, Mark 13:30 and Luke 21:32.
Then as an answer to him some of the scribes and Pharisees said: “Teacher, we want to see a sign from you.” In reply he said to them: “A wicked and adulterous generation keeps on seeking for a sign, but no sign will be given it except the sign of Jo′nah the prophet. For just as Jo′nah was in the belly of the huge fish three days and three nights, so the Son of man will be in the heart of the earth three days and three nights. Men of Nin′e·veh will rise up in the judgment with this generation and will condemn it; because they repented at what Jo′nah preached, but, look! something more than Jo′nah is here. The queen of the south will be raised up in the judgment with this generation and will condemn it; because she came from the ends of the earth to hear the wisdom of Sol′o·mon, but, look! something more than Sol′o·mon is here. “When an unclean spirit comes out of a man, it passes through parched places in search of a resting-place, and finds none. Then it says, ‘I will go back to my house out of which I moved’; and on arriving it finds it unoccupied but swept clean and adorned. Then it goes its way and takes along with it seven different spirits more wicked than itself, and, after getting inside, they dwell there; and the final circumstances of that man become worse than the first. That is how it will be also with this wicked generation.” Matthew 12:38-45
A wicked and adulterous generation keeps on seeking for a sign, but no sign will be given it except the sign of Jo′nah.” With that he went away, leaving them behind. Matthew 16:4
The generation referred to in Matthew 24:34 is a generation that would take note of foretold events in the last days.
Now learn from the fig tree as an illustration this point: Just as soon as its young branch grows tender and it puts forth leaves, you know that summer is near. Likewise also you, when you see all these things, know that he is near at the doors. Truly I say to you that this generation will by no means pass away until all these things occur. Heaven and earth will pass away, but my words will by no means pass away.
Concerning that day and hour nobody knows, neither the angels of the heavens nor the Son, but only the Father.
For just as the days of Noah were, so the presence of the Son of man will be. For as they were in those days before the flood, eating and drinking, men marrying and women being given in marriage, until the day that Noah entered into the ark; and they took no note until the flood came and swept them all away, so the presence of the Son of man will be. Then two men will be in the field: one will be taken along and the other be abandoned; two women will be grinding at the hand mill: one will be taken along and the other be abandoned. Keep on the watch, therefore, because you do not know on what day your Lord is coming. Matthew 24:32-42
More than once Jesus refers to whoever does God's will as his brothers.
While he was yet speaking to the crowds, look! his mother and brothers took up a position outside seeking to speak to him. So someone said to him:“Look! Your mother and your brothers are standing outside, seeking to speak to you.” As an answer he said to the one telling him:“Who is my mother, and who are my brothers?” And extending his hand toward his disciples, he said:“Look! My mother and my brothers! For whoever does the will of my Father who is in heaven, the same is my brother, and sister, and mother.” Matthew 12:46-50
“When the Son of man arrives in his glory, and all the angels with him, then he will sit down on his glorious throne. And all the nations will be gathered before him, and he will separate people one from another, just as a shepherd separates the sheep from the goats. And he will put the sheep on his right hand, but the goats on his left.
“Then the king will say to those on his right, ‘Come, you who have been blessed by my Father, inherit the kingdom prepared for you from the founding of the world. For I became hungry and you gave me something to eat; I got thirsty and you gave me something to drink. I was a stranger and you received me hospitably; naked, and you clothed me. I fell sick and you looked after me. I was in prison and you came to me.’ Then the righteous ones will answer him with the words,‘Lord, when did we see you hungry and feed you, or thirsty, and give you something to drink? When did we see you a stranger and receive you hospitably, or naked, and clothe you? When did we see you sick or in prison and go to you?’ And in reply the king will say to them,‘Truly I say to you, To the extent that you did it to one of the least of these my brothers, you did it to me.’ Matthew 25:31-40
More closely associated with Jesus are Kingdom heirs, the 140,000.
Jesus said to them:“Truly I say to you, In the re-creation, when the Son of man sits down upon his glorious throne, you who have followed me will also yourselves sit upon twelve thrones, judging the twelve tribes of Israel. Matthew 19:27-28
And I heard the number of those who were sealed, a hundred and forty-four thousand, sealed out of every tribe of the sons of Israel:
Out of the tribe of Judah twelve thousand sealed;
out of the tribe of Reu′ben twelve thousand;
out of the tribe of Gad twelve thousand;
out of the tribe of Ash′er twelve thousand;
out of the tribe of Naph′ta·li twelve thousand;
out of the tribe of Ma·nas′seh twelve thousand;
out of the tribe of Sim′e·on twelve thousand;
out of the tribe of Le′vi twelve thousand;
out of the tribe of Is′sa·char twelve thousand;
out of the tribe of Zeb′u·lun twelve thousand;
out of the tribe of Joseph twelve thousand;
out of the tribe of Benjamin twelve thousand sealed.
You are all, in fact, sons of God through your faith in Christ Jesus. For all of you who were baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither slave nor freeman, there is neither male nor female; for you are all one [person] in union with Christ Jesus. Moreover, if you belong to Christ, you are really Abraham’s seed, heirs with reference to a promise. Galatians 3:26-29
But you are “a chosen race, a royal priesthood, a holy nation, a people for special possession, that you should declare abroad the excellencies” of the one that called you out of darkness into his wonderful light. 1 Peter 2:9
The concept “generation” has more than one meaning in the Bible and in most dictionaries. Its context defines its meaning.
1. the entire body of individuals born and living at about the same time: the postwar generation.
4. a group of individuals belonging to a specific category at the same time
Matthew 24:34 has more application to a group of individuals belonging to a [specific category].
The unified generation that bore witness to all events during the Messiah's presence on earth and the sign of Christ's presence during the conclusion of the system of things was the 144,000 (individuals belonging to a specific category).
w70 6/1 p. 331 par. 22 Do You Have “Faith to the Preserving Alive of the Soul”?
The resurrection of the anointed Christians, who number 144,000, is to spirit life in heaven and it began to occur in 1918 C.E., after the establishment of the heavenly Kingdom in 1914.
The overlapping generations discussed at the latest District Assembly includes all of the anointed remnant of human's still alive during the conclusion of the system of things, but also includes the 144,000 in its entirety, as they're likewise living contemporaries of the modern anointed remnant.
This would include Jesus disciples, apostles and first century Christians that took note of events in the first century and the remaining remnant of the anointed class in the last days.
Matthew 24:34 applies to the 144,000.