The term “Son of Man” occurs repeatedly in the gospels as the way that Jesus most frequently refers to himself. Why is this, and what does the term mean? The fact that the term is limited almost exclusively to the gospel records also informs the meaning of Son of Man. There are at least three things one can say about the title, and its meaning.
Son of Man is a Messianic title. The use of Son of Man can be traced to Daniel 7:13-14, where the vision Daniel sees includes this:
“I saw in the night visions,
and behold, with the clouds of heaven
there came one like a son of man,
and he came to the Ancient of Days
and was presented before him.
And to him was given dominion
and glory and a kingdom,
that all peoples, nations, and languages
should serve him;
his dominion is an everlasting dominion,
which shall not pass away,
and his kingdom one
that shall not be destroyed.”
From Daniel, one can see that Son of Man is an ascription of Messianic identity. In applying it to himself as he repeatedly does, Jesus is making an overt and explicit claim to be Messiah. The second half of this passage further clarifies who Messiah is. He is the one to whom a kingdom is given, people – all people – will honor and serve him. No longer is it only the people, but peoples who will serve him, all the Gentile nations along with Israel. His kingdom is not temporal, but eternal. These things cannot be true of anyone but God. The Messiah therefore is identified as deity. No one but God is to be served everlastingly. This is important to see, because for those who aver that Jesus never made an explicit claim to be God, Son of Man is in fact just this.
When Jesus uses the term in the gospels, it comes with statements that reinforce these claims. “But that you may know that the Son of Man has authority on earth to forgive sins”—he then said to the paralytic—“Rise, pick up your bed and go home.” (Matt. 9:6). Recall that the scribes had murmured to themselves that Jesus was guilty of blasphemy, for no one but God had authority to forgive sins. In this they were indeed correct, but Jesus meets this not by opposing that assumption, but by affirming that he, as Son of Man, has the authority to forgive sins, because as Daniel makes plain, the Son of Man is a title of deity.
In John 5, Jesus makes a series of statements that are almost mathematical in their implication. If A = B and A = C, then A = C. “For as the Father raises the dead and gives them life, so also the Son gives life to whom he will. The Father judges no one, but has given all judgment to the Son, that all may honor the Son, just as they honor the Father.” (John 5:21-23) This culminates in Jesus’ claim that he possesses all authority to judge. “For as the Father has life in himself, so he has granted the Son also to have life in himself. And he has given him authority to execute judgment, because he is the Son of Man.” Here, again, the authority he has is linked to his being the Son of Man.
Why does Matthew have the preponderance of usages of the term? Messiah is preeminently the promised Messiah to Israel. He is her King and ruler. Secondly, the title also has to do with ruling on the earth, and the promises of earthly blessing are given to Israel, not to the church. This is why the usage of the term is so concentrated in those chapters where Jesus is teaching about his return and the judgment to come upon the earth. Matthew 24, the chapter when Jesus speaks of his return in power and glory, contains 6 references. The parallel passage in Luke has 4 occurrences.
Son of Man does not highlight Jesus as Head of The Church. After the gospels, the term occurs but once in Acts, when Stephen is about to die and sees the heavens opened, and says “I see the heavens opened, and the Son of Man standing at the right hand of God.” (Acts 7:56.) Recall that is was before a Jewish council, and the high priest that Stephen is witnessing, and this, too, makes sense. Importantly, the term Son of Man occurs in none of the New Testament epistles. Why is this? Again, it is because the term refers to Jesus in his office as Jewish Messiah, rather than Bridegroom or Head of church. Paul, more than anyone else, presents Jesus as head of the church, which is his body. It surely indicates this purpose that when speaking the body of Christ, no writer of an epistle ever references Son of Man when speaking of the Lord Jesus. Those in the body of Christ will not come into judgement to determine their eternal destiny. They have already been judged in the person of Christ on the cross. But those who are not in Christ will one day face judgement for their sins, and will stand before the Son of Man. This reflects the absence of the term in the epistles. When we come to the book of Revelation, the term reappears. And this, too, is fitting. The book has to do with judgments upon the earth, the sphere of the Son of Man’s authority. Yet because the Son of Man does not preeminently highlight Jesus in his relation to the church, this does not mean that Christians should not be interested or set aside all that it entails. On the contrary, we worship the Lord Jesus for all his manifold offices and glories.
Son of Man points to the Kingdom of God on the earth. The subject of prophecy is often fraught with difficulty and confusion. Many believers simply don’t study prophecy because it is perplexing. But I continually go back to something written by William Kelly on the topic. In his Lectures on the Book of Revelation, he notes:
“The objection to the study of prophecy arises from a root of unbelief, sometimes deeply hidden, which supposes all blessing to depend on the measure in which a subject bears immediately on one’s self or one’s circumstances. Thus when some cry out, That is not essential, I would ask, Essential to what? If they mean essential to salvation, we agree. On the other hand prophecy is essential to our due appreciation of Christ’s glory and of the glory that is to be revealed. To slight prophecy therefore is to despise unwittingly that glory and the grace which has made it known to us. It is the plainest evidence of the selfishness of our hearts, which wants every word of God to be directly about ourselves.”
In other words, if prophecy is primarily about what is future, rather than the here and now, this shouldn’t lessen our interest in it. It has to do with the revealing of Christ’s glory upon the earth. When the Son of Man comes in his glory, it will be for judgment and to establish his kingdom physically and visibly. In the prophets, there are numerous passages that put forth these Kingdom conditions. The Kingdom of God is such a vast topic, and so much the substance of Old Testament revelation that it is impossible to do justice to it briefly. But one can say that among the many promises about the Kingdom, its open manifestation is certainly among them. A couple of examples illustrate this. Hab. 4:2, “For the earth will be filled with the knowledge of the glory of the LORD as the waters cover the sea.” Is. 11:9, “They will not hurt or destroy in all My holy mountain, For the earth will be full of the knowledge of the LORD As the waters cover the sea.” This open manifestation of the Kingdom links to the Son of Man, and takes us back to Daniel 7, where dominion and rule are promised to the Son of Man. As you read the gospels, reflect on all the richness that this self-designation of Jesus means. If it is a promise of the glory to come, it is his glory, and therefore should interest every Christian.
 William Kelly, Lectures on the Book of Revelation (Bibles and Publications, Quebec, 1984), p.4-5.