Regardless of what we are now in our profession and career we all have earthly parents. They loved us and took care of us and when have children ourselves we in turn will love them and take care of them. Mary and Joseph loved Jesus and took care of him but Jesus identified himself not as a son Joseph and Mary but he preferred to call himself 'the Son of Man'. The title seems to indicate that this is something which is important for Jesus. When Jesus said that he was not denying the family relationship but he wanted to say something about his mission on earth. When call himself 'the Son of Man' Jesus reveals his true humanity. He identifies his life with every one of us and that He loves mankind and takes care of them all and expects them to love one another as He once gave the command.
Love one another as I have loved you. Jn 13:34
The teaching teaches us that there is a different between a human being and being a human. It is through the love God and the love we have for one another that we are truly being a human. The love of God transforms our lives and our way of thinking and thus leads us to live an unselfish life.
Second, in declaring himself 'the Son of Man' Jesus reveals that He is the Son of God, the divinity of Jesus. He is both God and man. Similarly we are children of our parents and when we profess God who is our Lord we are children of God.
The title 'the Son of Man' occurs numerous times in the New Testament. Its original meaning could be traced back in the prophecy of Daniel 7:13-14 and when Daniel talks about the cosmic son of man who was given authority, glory and sovereign power and all peoples and nations of every language must worship him. His reign and his kingdom have no end. The title 'the Son of Man' in Daniel's vision was a Messianic title. When Jesus used the title 'the Son of Man' the Jews of His time would have understood that Jesus proclaimed Himself as the Messiah. In short, the title 'the Son of Man' indicates that Jesus is truly God and truly man.
Both the images of a wheat grain that falls on the ground and dies and yields a rich harvest and the image of being 'lifted up from the earth to draw all to himself' reveal in a mysterious way the saving mission of Jesus. Both images tell us that there is life after death and the new life is far better than the present one.