The phrase “son of man” occurs in 178 verses in the Bible. Sometimes it’s written as “son of man” and other times, as “Son of man.”
When used as Son of man, the references are to Jesus, as seen in all four gospels (28 times in Matthew; 13 times in Mark; 25 times in Luke; and 12 times in John). It’s also written this way in Psalm 80:17, Daniel 7:13, and Acts 7:56, again implying Jesus.
Additionally, I understand “Son of man” as a euphemism for Son of God, which occurs 41 times throughout the New Testament and is in all four Gospels, all referencing Jesus.
What’s really interesting is the use of son of man. It’s used 93 times in the book of Ezekiel as God’s pet name for his prophet. But God also uses this as a name for Daniel (Daniel 8:17).
Three other mentions of son of man are in Hebrews 2:6, Revelation 1:13, and Revelation 14:14, which somewhat seems to straddle these two understandings of the phrase.
So, how can the Son of man refer to Jesus, while son of man refer to people?
Here are my thoughts: Jesus is the only son of God. We, as his church, are his bride. Therefore, through this spiritual marriage, we also become children of God, that is, sons of God, or to slide back into the euphemism, sons of man.