And he said to them, "I tell you the truth, some who are standing here will not taste death before they see the kingdom of God come with power. (Mark 9:1)
When you are persecuted in one place, flee to another. Truly I tell you, you will not finish going through the towns of Israel before the Son of Man comes - Matthew 10:23
24 “But in those days, after that tribulation, the sun will be darkened and the moon will not give its light , 25 and the stars will be falling from heaven, and the powers that are in the heavens will be shaken. 26 Then they will see the Son of Man coming in clouds with great power and glory. 27 And then He will send forth the angels, and will gather together His elect from the four winds, from the farthest end of the earth to the farthest end of heaven....... 30 Truly I say to you, this generation will not pass away until all these things take place. (Mark 13:24-27,30)
These verses clearly show that Jesus believed that the kingdom of God together with his second parouxia would come in his generation, and not after that. If all these things did not happen in those days, we have no choice, Jesus was a false prophet. It is pointless to separate the events of Jerusalem's destruction (70 AD) with those of the second coming, because they are conected as we read above. Unless Jesus did not say the above words and Mark misquoted Peter (if Papias told us the truth about Mark's authorship).