Jesus used the epithet Son of Man when he was referring to himself as a product of the world and humanity, i.e. his human personality and body.
When he used the epithet Son of God he was referring to the part of himself which was related to God, i.e. his soul or spirit.
We are all products of both the world and God.
We all have personalities which have been formed by reaction to the world around us and our experiences in the world.
We also have aspects of ourselves which are created and formed by God.
This is where Jesus got into trouble with the Pharisees. It was O.K. for him to call himself Son of Man because that meant to them that he was born in sin and therefore in need of redemption (through them).
It was not O.K., however, for Jesus to call himself Son of God because that meant that he had some sort of relationship with God which was outside of their control.
"''And call no one your father on earth, for you have one Father - the one in heaven.'" Matthew 23:9 (NRSV)
And therein lies the problem. We don't need the Pharisees in order to have a relationship with God.
That is not to say that God is not there - in His house.
That is why Jesus goes to Jerusalem - to go to God's house.
When he gets there, however, he behaves unpredictably. He criticizes the authorities. He says that they have perverted God's message. Turning love and compassion into privilege and profit.
They crucified him for that.
Why does God not stop them?
Perhaps He cannot stop them.
They will not listen to Him speaking through His prophet.
And God does not use force.
"'For I tell you, you will not see me again until you say,"Blessed is the one who comes in the name of the Lord."'" Matthew 23:39 (NRSV)
"'Wherever the corpse is, there the vultures will gather.'" Matthew 14:28 (NRSV)
The Pharisees have usurped the power of God (the Temple) for their own profit.
And they do not share power.
So we are all Sons of Man and Sons of God.
Our task is to return the message of love and compassion to its rightful place in God's house.
Until them the blind lead the blind.
(Scripture quotations (marked NRSV) are taken from the New Revised Standard Version Bible, copyright 1989 by the Division of Christian Education of the National Council of the Churches of Christ in the U.S.A., and are used by permission. All rights reserved.)