Fulfilled immediately afterwards in His transfiguration on the mountain with Moses and Elijah, seen by Peter, James and John.
Many scholars have moved away from that interpretation due to Mark, which is believed to be the first gospel written, states “come with power”. The word “come” displaying completeness. The transfiguration did not demonstrate that the kingdom had come with completeness. The coming of the kingdom of God would come completely through the death, resurrection, and ascension of Christ, sending of the spirit, the going of the gospel to the nations, and ultimately in the destruction of Jerusalem in 70ad.
See the following scholarly commentaries:
Ellicot
“The immediate sequence of the vision of the Son of Man transfigured from the low estate in which He then lived and moved, into the “excellent glory” which met the gaze of the three disciples, has led not a few interpreters to see in that vision the fulfilment of this prediction.
A closer scrutiny of the words must, however, lead us to set aside that interpretation, except so far as the Transfiguration bore witness to what had till then been the latent possibilities of His greatness. To speak of something that was to take place within six days as to occur before some of those who heard the words should taste of death (comp.
John 8:52,
Hebrews 2:9, for the form of the expression) would hardly have been natural; nor does the vision, as such, satisfy the meaning of the words “coming in His kingdom.” The solution of the problem is to be found in the great prophecy of Matthew 24. In a sense which was real, though partial, the judgment which fell upon the Jewish Church, the destruction of the Holy City and the Temple, the onward march of the Church of Christ, was as the coming of the Son of Man in His kingdom. His people felt that He was not far off from every one of them. He had come to them in “spirit and in power,” and that advent was at once the earnest and the foreshadowing of the “great far-off event,” the day and hour of which were hidden from the angels of God, and even from the Son of Man Himself (
Mark 13:32). The words find their parallel in those that declared that “This generation shall not pass away till all be fulfilled” (
Matthew 24:34). That such words should have been recorded and published by the Evangelists is a proof either that they accepted that interpretation, if they wrote after the destruction of Jerusalem, or, if we assume that they were led by them to look for the “end of all things” as near at hand, that they wrote before the generation of those who then stood by had passed away; and so the very difficulty that has perplexed men becomes a proof of the early date of the three Gospels that contain the record.”
Benson
“Accordingly the disciples saw their Master coming in his kingdom, when they were witnesses of his transfiguration, resurrection, and ascension, and the miraculous gifts of his Spirit conferred upon them; and lived to see Jerusalem, with the Jewish state, destroyed, and the gospel propagated through the greatest part of the then known world.”
Cambridge
“The expression is referred to (1) the Transfiguration, (2) the Day of Pentecost, (3)
the Fall of Jerusalem. The last best fulfils the conditions of interpretation—a judicial coming—a signal and visible event, and one that would happen in the lifetime of some, but not of all, who were present.”
Pulpit
“This advent is doubtless the destruction of Jerusalem, which, as it occurred only some forty years after this time, some of his auditors, apostles and the multitude, would live to behold”
There is no evidence that they ever proselytized any of the cities of Judah/Southern Israel in their day.
Right, doesn’t the passage say they would “not” go through all the cities of Israel before the son of man comes?
The "this [
literally, the same] generation" refers to the generation of the fig tree putting forth leaves, which is End Times.
1.) Jesus did not say “that” generation. He said “this” generation. “That” would be more grammatically appropriate if he was talking about a future “fig tree” generation.
2.) Did Jesus’ generation experience wars, rumors of wars, famines, false prophets, persecution, the gospel going to the whole “oikoumene”, the end of the age, the destruction of the temple and city? If Yes, then “this” generation appropriately applies to Jesus’ generation that literally did live through those events.