Is the Second Coming of Jesus true?

According to the Gospel, Jesus had once revealed His Second Coming to the disciples:

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In the Book of Mark 13, Jesus said to his disciple, "But in those days, following that distress, the sun will be darkened, and the moon will not give its light; the stars will fall from the sky, and the heavenly bodies will be shaken. At that time men will see the Son of Man coming in clouds with great power and glory …… I tell you the truth, this generation will certainly not pass away until all these things have happened."

Apostle Paul interpreted Jesus' saying of His Second Coming as imminent and would take place before he died:

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In the Book of 1 Thessalonians 4, it says, 'We believe that Jesus died and rose again and so we believe that God will bring with Jesus those who have fallen asleep in him ...... After that, we who are still alive and are left will be caught up together with them in the clouds to meet the Lord in the air. And so we will be with the Lord forever.'

However, it is obvious that the Second Coming of Jesus as understood by the disciples did not happened in their generation and their hope disappointed:

In 2 Peter 3, it says, "Where is this 'coming' he promised? Ever since our fathers died, everything goes on as it has since the beginning of creation …… But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day."
According to Marcus Borg's The Meaning of Jesus, there are two possibilities. Either, the apocalyptic eschatology goes back to Jesus Himself but the meaning was misunderstood by his immediate successors including Apostle Paul. Or, the expectation of the Second Coming of Jesus was a product made up by Early Christians movement after Jesus death. Let us examine the authenticity of the Gospel's record of Jesus' saying by the following criteria:

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Criterion of Embarrasement

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The recorded saying was considered by the early post-Easter Christian as awkward, contrary to the editorial tendency and as in need of qualification or even deletion, but the material was preserved despite the awkwardness and potential embarrassment. Under this criterion, the recorded saying may be considered authentic.

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Criterion of Multiple Attestation

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The recorded saying of Second Coming was mentioned in two or more independent sources like the Book of John, the Book of Revelation, and the letters of Apostle Paul including the First Book of Thessalonians and Corinthians which are commonly considered to be written at a much earlier time than the Books of Gospel. However, under this criterion, it can only be regarded as primitive rather than authentic.

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Criterion of 'Aftermath'

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As recorded in the Book of Acts 2:42-47, the early post-Easter Christians had everything in common and sold their possessions and goods, they gave to anyone as he had need. Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts, praising God and enjoying the favor of all the people. It seems that the early post-Easter Christian strongly believed that the coming of Christ was near. Under this criterion, the recorded saying may be considered authentic.

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Criterion of Historical Plausibility

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Jesus could only say what a first century Jewish charismatic or prophet could have said. This was possible according to the prophesies of the Old Testament. Under this criterion, the recorded saying may be considered authentic.

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Criterion of Discontinuity

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The recorded saying was not dissimilar to both contemporary Judaism and the early post-Easter Christian. Resurrection was seen as an 'end-time' event in Judaism. The conviction that Jesus had been resurrected led to the inference that the end is near. Moreover, the destruction of the Jerusalem Temple in AD 70 also led to the sense that the end is at hand and the early post-Easter Christian thought so.

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A Challenging Question

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If Marcus' hypothesis, i.e. the early post-Easter Christians misunderstood the Second Coming, or the record of Jesus' saying was just a product of the early post-Easter Christians for the purpose of thelogical representation, are false, the only option left may be that our conception of Jesus' Second Coming is false.

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Some minor 'Christian' sects, like Jesus Seminar which Marcus Borg belongs to, believes that the Second Coming of Jesus has already taken place. The Kingdom of God is just 'here and now', and they have no concern on any futuristic kind of eschatology. Will you maintain your Chrisitan life and be faithful to God if the Kingdom of God is just 'here and now'? If they can sustain their 'Christian' life just by the belief of the 'here and now' Kingdom of God, can we say that they have greater love than us?