A Christian that was not desperate would own up to the failures of the Bible.
An atheist would be doing that and most likely a false Christian too.
I have read Luke 21:29-32 but I have moved up the verses from 5-32 so we could see the whole picture. Reading 29-32 is insufficient to view the whole context. It would be like watching the ending without the whole scene thus spoiling the fun. So here it goes, I have inserted my comments in [blue] and some pictures / references:
Luke 21:5-32 New International Version (NIV)
Some of his disciples were remarking about how the temple was adorned with beautiful stones and with gifts dedicated to God. But Jesus said, “As for what you see here, the time will come when not one stone will be left on another; every one of them will be thrown down.”
Second Temple - Wikipedia
“Teacher,” they asked, “when will these things happen? And what will be the sign that they are about to take place?”
He replied: “Watch out that you are not deceived. For many will come in my name, claiming, ‘I am he,’ and, ‘The time is near.’ Do not follow them. When you hear of wars and uprisings, do not be frightened. These things must happen first, but the end will not come right away.”
Then he said to them: “Nation will rise against nation, and kingdom against kingdom. There will be great earthquakes, famines and pestilences in various places, and fearful events and great signs from heaven.
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But before all this, they will seize you and persecute you. They will hand you over to synagogues and put you in prison, and you will be brought before kings and governors, and all on account of my name. And so you will bear testimony to me. But make up your mind not to worry beforehand how you will defend yourselves. For I will give you words and wisdom that none of your adversaries will be able to resist or contradict. You will be betrayed even by parents, brothers and sisters, relatives and friends, and they will put some of you to death. Everyone will hate you because of me. But not a hair of your head will perish. Stand firm, and you will win life.
Martyrdom of the Apostles
“When you see Jerusalem being surrounded by armies, you will know that its desolation is near. Then let those who are in Judea flee to the mountains, let those in the city get out, and let those in the country not enter the city. For this is the time of punishment in fulfillment of all that has been written. How dreadful it will be in those days for pregnant women and nursing mothers! There will be great distress in the land and wrath against this people. They will fall by the sword and will be taken as prisoners to all the nations. Jerusalem will be trampled on by the Gentiles until the times of the Gentiles are fulfilled.
In 66 CE the Jewish population rebelled against the Roman Empire. Four years later, in 70 CE, Roman legions under Titus retook and destroyed much of Jerusalem and the Second Temple.
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There will be signs in the sun, moon and stars. On the earth, nations will be in anguish and perplexity at the roaring and tossing of the sea. People will faint from terror, apprehensive of what is coming on the world, for the heavenly bodies will be shaken.
At that time they will see the Son of Man coming in a cloud with power and great glory. When these things begin to take place, stand up and lift up your heads, because your redemption is drawing near.”
This has yet to happen, in the Second Advent of our Lord Jesus Christ and does not pertain to the time of the apostles. It will happen in the near future at the time the Son of Man would come in a cloud with power and great glory.
He told them this parable: “Look at the fig tree and all the trees. When they sprout leaves, you can see for yourselves and know that summer is near. Even so, when you see these things happening, you know that the kingdom of God is near.
“Truly I tell you, this generation will certainly not pass away until all these things have happened.
The destruction of Jerusalem as foretold by the Lord Jesus Christ [40? years before it actually happened] was fulfilled during the apostles' timeline and the generation whom the Lord Jesus pertains to.
The Romans Destroy the Temple at Jerusalem, 70 AD
Conclusion: The prophecies of the Lord Jesus Christ were true, fulfilled and will be fulfilled in the future. The prophecies are not over but will see their light of day.
2 Peter 1:19-21 New International Version (NIV)
We also have
the prophetic message as something completely reliable, and you will do well to pay attention to it, as to
a light shining in a dark place, until the day dawns and the morning star rises in your hearts. Above all, you must understand that no prophecy of Scripture came about by the prophet’s own interpretation of things. For
prophecy never had its origin in the human will, but prophets, though human, spoke from God as they were carried along by the Holy Spirit.