In the Gospels Jesus referred to himself as the Son of Man 85 times. Why would the Son of God’s favorite designation for himself be Son of Man? In his conversation with the disciples in Mark 10 he gives us some insight:
And Jesus called them to him and said to them, “You know that those who are considered rulers of the Gentiles lord it over them, and their great ones exercise authority over them. But it shall not be so among you. But whoever would be great among you must be your servant, and whoever would be first among you must be slave of all. For even the Son of Man came not to be served but to serve, and to give his life as a ransom for many.” (Mark 10:42-45 ESV)
The simple meaning of Son of Man is that Jesus was human. He was born of a woman like other men. He grew up like other children. He got hungry and thirsty. He experienced loneliness and exhilaration. He was the Son of Man.
Yet he was the Son of God. As the Son of God he was unlike any other human being. He was born of woman, conceived by the Spirit. He grew up like other children yet unlike other children. Luke tells the story:
After three days they found him in the temple, sitting among the teachers, listening to them and asking them questions. And all who heard him were amazed at his understanding and his answers. And when his parents saw him, they were astonished. And his mother said to him, “Son, why have you treated us so? Behold, your father and I have been searching for you in great distress.” And he said to them, “Why were you looking for me? Did you not know that I must be in my Father’s house?” (Luke 2:46-49 ESV)
As the Son of God he longed to be in His Father’s house.
Why would the Son of God’s favorite title for himself be, not the Son of God, but the Son of Man? Because he came, not to be served, but to serve and to give his life a ransom for many. God, by his very nature, must be served. No one is higher than Him, no one more deserving of praise, no one more deserving of glory. He must be served.
In Jesus the served became the servant, the glorified became crucified, the holy was humiliated. At the very heart of Christianity is selfless service because we worship the Son of God who was the Son of Man.