The concept of Jesus is a bit confusing to me. Is he God's son or God himself in human form? But if Jesus is god, how can he be God's son?
Was he a average joe who got possessed by God? What exactly was Jesus?
The term "son of God" actually has several different meanings, all of which apply to Jesus in different ways:
* In OT language it could be used for a godly man. But it can specifically refer to the King, as in Psalm 2, a passage which is quoted in the NT. So it can refer to Jesus as Messiah.
* Jesus referred to God as his Father. Although he wanted us to see God the same way, I'd say he was the son specifically. So in this context it refers to a particularly close relationship with the Father, which however is appropriate for a human.
* In the Gospels it refers to a specific role that Jesus carried out. E.g. unclean spirits recognize him as the Son of God. So does Satan (luk 4:3). Luk 4:41 seems to equate this with being the Messiah, which makes sense.
* John sees it as a reference to Jesus as the Word made flesh. See e.g. 1:18. There are several other classic Christological passages that make a similar point.
* In the doctrine of the Trinity it refers to the relationship between the eternal Logos and the Father. Note that in the Trinity the Son is called Son to emphasize that he is truly God from God. Sons are born, and are like their fathers. This is in opposition to Arius, who saw the Logos as a created being, and not fully God. Note however that Jesus is the word *made flesh*, i.e. the incarnation of the Logos. Son in the sense of fully equal to God applies primarily to the eternal Logos, not to the human. The human as human is clearly not pure spirit, omnipotent, etc. However because the Logos and the human are united as one person, that person shows us what the Logos is like and thus he shows us God in his fulness even though he has all the usual human limitations.
I'd say that in the NT it refers to Jesus' special role as God's human presence. The Trinity is a later way of understanding that. But the Bible isn't as specific about just how God is present through Jesus.