You offered the following solutions:
- The Son of Man coming in his kingdom (Mark 9:1 // Mt. 16:28 // Luke 9:27) may have referred to the transfiguration. (suggested by James)
- In context, Mark 13:29-30 (// Mt. 24:34 // Luke 21:32) may have referred to the destruction of Jerusalem. (again, James)
- Perhaps Jesus meant only that his prophecies about the end times will all be fulfilled within the scope of a lifetime. (suggested by Cliff)
- The prophecy may have been conditional. (Jamie)
- Finally, John observed that we must also keep in mind Mark 13:32 ("But concerning that day or that hour, no one knows, not even the angels in heaven, nor the Son, but only the Father") and Acts 1:7 ("It is not for you to know times or seasons that the Father has fixed by his own authority").1
We'll come back to John's comment below. I think it's an important counterweight to the appearance of watertight certainty that the other sayings possess.
As for your other suggestions, I think they all have merit. Meanwhile, the fact that there are so many attempts at a solution is evidence that interpreters have struggled to understand Jesus' sayings over the years.
In this post, I want to offer three theological concepts which, taken together, at least reduce the magnitude of the problem.
1. Now and not yet:
In my view, Jesus' prediction was fulfilled in part. The New Testament authors generally agree that the kingdom of God was inaugurated with (a) Jesus' resurrection followed by (b) the pouring out of the Holy Spirit.
Both are eschatological events — both were supposed to happen at the end of history, not part way through history. That's why St. Paul refers to the resurrection (1Co. 15:20) and the indwelling Spirit (Ro. 8:23) as "firstfruits". Again, Paul speaks of the Holy Spirit as a down payment. We have received a partial fulfillment now, guaranteeing that a perfect fulfillment will follow in due course.
The eschaton has been inaugurated (it is "now") but not consummated (it is "not yet"). This is the first theological concept we must bear in mind. Scholars use this terminology, now and not yet, to capture the paradoxical nature of the church age. John's Gospel provides a classic example of this now/not yet tension at 5:25 —
Truly, truly, I say to you, an hour is coming, and is now here, when the dead will hear the voice of the Son of God, and those who hear will live.The concept implies that Jesus' prediction was fulfilled, if only in part. It also explains why the first generation of Christians lived in such fervid expectation of Christ's return. First there were Jesus' predictions; then those predictions were followed by unmistakably eschatological events. Surely Jesus' return could not lag far behind!
2. Jesus' self-emptying:
But Jesus did not return immediately, and so the question persists. Did Jesus err, at least in part?
In my view, there's no getting around it: what happened wasn't exactly what Jesus expected and confidently predicted. Here we must return to the sayings John called to our attention — particularly Mark 13:32.
But concerning that day or that hour, no one knows, not even the angels in heaven, nor the Son, but only the Father.This saying is another problem passage. At least, it's problematic for folks who assume that Jesus possessed all of the divine attributes, including omniscience, even during the period of his incarnation. And yet St. Paul says that Jesus "emptied" himself (Php. 2:7, NRSV) during the period of his ministry.
This self-emptying (Gk. kenosis) is the second theological concept we must bear in mind. Logically, Jesus would have to divest himself of at least some of the divine traits in order to be considered fully human. To be human is, by definition, to be subject to limitations which cannot apply to God.
And so it is with Mark 13:32, where Jesus admits that his knowledge of "that day or that hour" is finite. It seems that Jesus, like Paul, could prophesy only "in part".
Robert Peterson introduces a helpful distinction.2 I have added numbering and italics to his presentation for greater clarity:
To understand the timing of the second coming, we have to deal with all the information God gives us, and that information falls into three categories, three types of passages.… It seems to me that if we hold these three things together, we will be much better off.
- There are imminence passages, which cause people to look for Jesus to come.
- There are interval passages, which indicate certain things have to happen before He comes.
- And most importantly, there are ignorance passages, which tell us that we do not know, that nobody knows, the day or the hour.
3. Prophetic foreshortening:
Finally, let me observe that the prophecy in Mark 13 is an outstanding example of "prophetic foreshortening". This is the third theological concept that we must bear in mind. It is a commonplace of prophecy that events which are separated by centuries of history are "foreshortened", or telescoped together in the prophet's message.
One classic illustration involves someone looking at a mountain range from a distance. (Please excuse my lack of artistic talent!)

The general significance of the illustration is as follows. From a distance, the mountain peaks appear to be close together. It is only as you arrive at the first peak that you realize the second peak is actually quite distant.
Turning to the specific problem of Mark 13 and parallels —
Point 1 marks the destruction of Jerusalem in 70 CE. Point 2 marks 2,000 years (and counting) of Church history. That timespan was evidently hidden from Jesus; at any rate, it doesn't feature in the sayings we have been considering. Point 3 marks the parousia (Second Coming).
In his predictions, Jesus jumbled these events together as if they were all part of the same constellation. And indeed, some of the events may ultimately be fulfilled twice: for example, an intense persecution of the Church and the coming of false Messiahs. Those predictions may have been fulfilled at point 1 in my diagram. (Josephus spoke of false prophets, who may in fact have been messianic pretenders.) It doesn't mean that there won't be a second fulfillment when history arrives at point 3.
For another example of prophetic foreshortening, consider Joel 2 (= Acts 2):
For these people are not drunk, as you suppose, since it is only the third hour of the day. But this is what was uttered through the prophet Joel:Here we see the pouring out of the Holy Spirit packaged with the arrival of the eschaton. And indeed, this foreshortening phenomenon is a commonplace of biblical prophecy (particularly with respect to eschatological events).
"'And in the last days it shall be,' God declares,
'that I will pour out my Spirit on all flesh,
and your sons and your daughters shall prophesy,
and your young men shall see visions,
and your old men shall dream dreams;
even on my male servants and female servants
in those days I will pour out my Spirit, and they shall prophesy.
And I will show wonders in the heavens above
and signs on the earth below,
blood, and fire, and vapor of smoke;
the sun shall be turned to darkness
and the moon to blood,
before the day of the Lord comes, the great and magnificent day.
And it shall come to pass that everyone who calls upon the name of the Lord shall be saved.'"
(Acts 2:15-21)
Conclusions:
- The several suggestions offered in response to my previous post testify that there is no completely satisfactory solution to the problem I outlined.
- Several of the suggestions also testify to a partial fulfillment of Jesus' prophesies. In particular, I would emphasize Jesus' resurrection and the pouring out of the Holy Spirit at Pentecost. According to Acts 2, the pouring out of the Holy Spirit on Jesus' disciples is evidence that he had been exalted to the right hand of God, and installed as king (= Christ).
And yet there is a remainder — various elements of Jesus' expectation which have not yet been fufilled. This unexpected development, a partial fulfillment of prophecy, is articulated in the theological expression, now and not yet. - In my view, the events were not quite as Jesus had anticipated and predicted. But perhaps this is only what we might have expected. St. Paul speaks of Jesus' self-emptying (kenosis), and Jesus confessed that his knowledge of eschatological events was limited.
- We should compare Jesus' partially fulfilled prophecies with the general pattern of prediction and fulfillment in the Bible. At that point, we may be surprised to realize that prophetic foreshortening is a commonplace of biblical prophecy (i.e., a clustering together of events that turn out to be separated by centuries of history).
- Finally, I wish to reiterate the point that I made in the conclusion of my previous post. That these (and other) "hard" sayings of Jesus were preserved in the Gospels testifies to the Evangelists' unwillingness to destroy authentic tradition. This conservative impulse reassures us that the Gospels are a trustworthy source of information about the historical Jesus.

This work is licensed under a Creative Commons Licence.
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1Unless otherwise indicated, scripture is quoted from The Holy Bible, English Standard Version.
2I believe Peterson is crediting David Jones for the three-part categorization of scripture mentioned above.