Part 1 is available here, Part 2 here, Part 3 here, Part 4 here, and Part 5 here.
AP: So how do we account for the way the "Son of Man" sayings were ascribed to Jesus? Well, one hypothetical solution could go as follows:
1. It was probably based on a clear and verifiably historical premise: Jesus used this enigmatic phrase in reference to himself, to allude to himself in a modest sort of way (i.e., "this man who is here and speaking to you"). We said that this is something of which there is no doubt because it of multiple attestation in the Gospels and because it was an Aramaic expression used during Jesus' day, although not really that often. One example is found in Mark 2:28: "The Sabbath was made for man and not man for the Sabbath. So the Son of Man is also Lord of the Sabbath."
2. Jesus, influenced by and according to the tradition of Daniel, also spoke of a semihuman figure, a "son of man" who would come in the name of God as judge of the living and the dead in the last days, referring most probably to what we have called the second and definitive part of the kingdom of God. For example, Mark 8:38: "For whoever is ashamed of me and of my words in this adulterous and sinful generation, the Son of Man will be ashamed of him when he comes in the glory of his Father with the holy angels."
3. When the sayings of Jesus were translated from Aramaic to Greek as part of the missionary work that was being done, an error of translation was committed that had serious consequences. Instead of "son of man" (without the article) in Daniel, it was translated into Greek "the son of the man," with two articles. This led one to think that the phrase––not as easily understood by a regular Greek––meant not merely "a human being," though certainly close to God, but a man with special, messianic divine characteristics.
4. The erroneous translation into Greek thus led to expressly relating the expression "the son of man" to the mysterious figure of "a son of man" in Daniel (7:13). This apocalyptic character, who descends to earth from heaven and who "receives the dominion, the glory, and a kingdom," that is, implants the kingdom of God, has in common with the Jesus of history the fact that the central nucleus of his preaching was precisely the coming of the kingdom of God from which he was considered a herald.
5. After the firm belief in Jesus' resurrection had spread among the followers of Jesus, the early Christian teachers affirmed that Jesus, as a special messiah and "Son of Man" (he himself had used the expression!), would come upon the clouds of heaven (Dan. 7:13) . . . naturally to judge all nations, which we see if we continue reading that passage in Daniel.
The resurrection of Jesus by God implied a vindication of him over his enemies. The Christians affirmed that with that vindication it was united that God declared him "Lord and Messiah" (Acts 2:36). "Lord," for to be beside him in heaven he must have a delegated power similar to that of the divinity for some things. "Messiah," because God does not leave things half-done. Since Jesus could not complete his messianic work during his mortal life, he will have to complete it now, after his death.
It should be emphasized that it was not at all difficult, in this testament of the reinterpretation of life and the figure of Jesus, for the early Christians to associate the messianic function of Jesus after his death and resurrection with the messianic function of that mysterious figure of Daniel. Christians thought that all the ancient Scriptures pointed to Jesus ("promise" = Scripture / "fulfillment" = Jesus). It didn't take long for followers of Jesus to view Jesus as is in heaven and waiting for God's command to return to earth with his new mission, namely that of the Son of Man.
That figure is at least semi-divine, but one in human form. He took on this form because he will operate on earth as the lieutenant of a transcendent divinity that does not operate in the universe more than indirectly. This one will be visible to men, they will feel the effects of their actions and of their decisions and therefore has a similar figure to them. But in the first-century Jewish religious conception, as we know from the Qumran texts, especially from 11QMelchizedek, this mysterious person is not simply a common man on earth, but preexists as God and awaits the moment decided by God.
That this theological step was really taken––that is, applying to Jesus a passage from Scripture––has been captured in two passages of the Acts of the Apostles. The first: Stephen the deacon, at the time when the Jews were stoning him precisely because he was formulating a new and dangerous theology that exalted Jesus too much, exclaimed: "Behold, I see the heavens opened, and the Son of Man that is at the right hand of God." This phrase already implied a union of the figure of Jesus with that of the Son of Man found in Daniel. The second: Peter put forth the same idea but spontaneously complemented it with the role of future judge, as found in a discourse in Caesarea before pagans: "God has commanded us to preach to the people and to testify that he, God, has made him a judge of the living and the dead."
6. With this belief, the Christian prophets, speaking in the name of Jesus, who were convinced that the end of the world was very close, and that Jesus Christ was to come immediately to install the kingdom of God, which implied the end of the present world, they spoke in the name of the Master, announcing that they had to believe in him if they wanted to escape punishment at the end of days. For example, something like: "You will see the Son of Man seated at the right hand of God's power and coming in the clouds of heaven." One observation is pertinent here. It points to the active participation of the Christian prophets: in these sayings Jesus never speaks, or almost never, in the first person. What is said about the "Son of Man" always seems to be said by others about him.
7. Finally, the oracles of these prophets pronounced in the name of Jesus then passed on to the tradition that picked up the words of this one without even a hint that they weren't original, as if Jesus had really said them during his earthly life. In other words, they didn't transcribe this information in the following way: "A Christian prophet said that Jesus said . . ." They just simply said, "Jesus said . . ."