(Your citing)
34 Verily I say unto you, This generation shall not pass, till all these things be fulfilled.
In keeping with Jesus' Rules of parable understandings from Mark 4:13-15, we should be able to see that there are 3 partys involved with every parable. God, mankind and the devil (and his messenger-devils).
Are they also a generation, singular? Indeed:
Matthew 12:34
O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.
Matthew 23:33
Ye serpents, ye generation of vipers, how can ye escape the damnation of hell?
Easy to see in the above that the serpents, the vipers, which are terms for DEVILS, have "a generation" singular tense. Why is it singular tense. Because none of them have yet passed away.
So what generation, singular, shall not pass away until all things are fulfilled? The generation of the devil and his messengers. The study of the singular term, generation in the scriptures will hold to the above principle.
This same principle is also applied to these scriptures:
Matthew 16:28
Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom.
Luke 9:27
But I tell you of a truth, there be some standing here, which shall not taste of death, till they see the kingdom of God.
Many have mangled the above scriptures when they FAIL to see that Jesus often addresses the DEVIL or DEVILS in mankind. They end up tagging Jews of that time and end up in partial or full preterism trying to make the verses "fit" what they think, but they MISS the obvious.
When this party the devil and his own, that are not mankind is void from parable dissections, the understandings of parables are likewise VOID of the obvious.
So, when Jesus Returns, this is what happens:
Rev 1:
7 Behold, he cometh with clouds; and every eye shall see him, >>>and they also which pierced him:<<< and all kindreds of the earth shall wail because of him. Even so, Amen.
IF we think it's just mankind that will be seeing Jesus' return, think again. There are also entities unseen, the devil and his messengers IN MANKIND that will also SEE this return. Even those who pierced him were what? That's right. Blinded slaves of the DEVIL. Those "devils" are still here. Still standing in some people. When their "flesh host" man dies, they just hop on another flesh slave. And on this has transpired, from the beginning.