The Certain Sign. 28 “Learn a lesson from the fig tree. When its branch becomes tender and sprouts leaves, you know that summer is near. 29 In the same way, when you see these things happening, know that he is near, at the gates. 30 Amen, I say to you, this generation will not pass away until all these things have taken place. 31 Heaven and earth will pass away, but my words will not pass away.
The image of the fig tree in blossom is a sure and certain sign of summer. Jesus is using a short proverb to assure the readings that his promises are true. So, when they see these things happening they will know. But what are “these things?” Is the reader supposed to remember the fig tree with leaves and no fruit, which Jesus cursed (11:12–14, 20–22)? If so, then alleged “signs” must be carefully scrutinized. Who is “near”? God? A Son of Man other than Jesus? Jesus as Son of Man? What are “these things”?
At the very beginning of Mark 13, immediately following upon last week’s Gospel (the Markan version of the Widow’s mite), we read:
1 As he was making his way out of the temple area one of his disciples said to him, “Look, teacher, what stones and what buildings!” 2 Jesus said to him, “Do you see these great buildings? There will not be one stone left upon another that will not be thrown down.” 3 As he was sitting on the Mount of Olives opposite the temple area, Peter, James, John, and Andrew asked him privately, 4 “Tell us, when will this happen, and what sign will there be when all these things are about to come to an end?”
The verses above (vv.24-27) referred to the second coming, not the destruction of the Temple. While it is possible the signs of vv.21-24 are coterminous with the destruction of the Temple hinted at v.2, there may be another possibility:
14 “When you see the desolating abomination standing where he should not (let the reader understand), then those in Judea must flee to the mountains, 15 (and) a person on a housetop must not go down or enter to get anything out of his house, 16 and a person in a field must not return to get his cloak. 17 Woe to pregnant women and nursing mothers in those days. 18 Pray that this does not happen in winter. 19 For those times will have tribulation such as has not been since the beginning of God’s creation until now, nor ever will be. 20 If the Lord had not shortened those days, no one would be saved; but for the sake of the elect whom he chose, he did shorten the days. 21 If anyone says to you then, ‘Look, here is the Messiah! Look, there he is!’ do not believe it. 22 False messiahs and false prophets will arise and will perform signs and wonders in order to mislead, if that were possible, the elect. 23 Be watchful! I have told it all to you beforehand. (Mark 13:24-23)
The problem that presents itself is that it is possible in Mark (definite in Luke and Matthew) that the 70 AD destruction of Jerusalem and the Temple was already a historical fact – and yet the Son of Man did not literally come again – and yet He has ascended his throne in heaven. It is not clear what is being said. Perkins  offers that “The earlier sections of the chapter appear to distance the destruction of the Temple and turmoil surrounding the Temple from the end time. The saying about the fig tree may have been intended by Mark to convey reassurance rather than information; as Christians begin to see events that conform to these predictions, they are assured that the day of salvation for the elect is near.”
Chad Myers (Binding the Strong Man: A Political Reading of Mark’s Story of Jesus) agrees with most commentators that Mark was written during the Jewish revolt against Rome (66-70 AD), but, in addition, that Mark is encouraging his community not to participate in the rebel’s revolt. The “false prophets” are those zealots who claim that their victory over Rome will usher in the new age. For “Mark,” the war is not a sign of the end, but only of the beginning. Myers  writes concerning the opening of ch. 13:
The fact that the parties of the revolt are never mentioned by name in the Gospel may indicate that Mark felt deeply sympathetic to their protest against the social, political, and economic oppression of the Romans. On the other hand, the fact that Mark feels a need to reject the claims of the rebel recruiters suggests that members of Mark’s community may well have already been drafted into the liberation war, or were sorely tempted to join. Who could resist the pull of patriotism, or the lure of the hope that here at last was the long-deferred prophetic promise of that final battle in which Yahweh would vindicate Israel? In such a moment, there was only one voice that could match the persuasive call of the rebel recruiters: Jesus the living teacher. So to this Jesus the disciples turn in a direct plea for clarity on the meaning of the historical moment.
The destruction of the Jerusalem Temple did indeed happen as noted in v.30: “Amen, I say to you, this generation will not pass away until all these things have taken place.” The events of 70 AD were not the harbinger of the Second Coming/parousia, but it was a harbinger of the community of Christian Jews soon taking on an identity of Christian with its roots in Judaism and its eyes on the Christ.