>many christians think that Jesus was the only son of god,
>w/o realising that the father-son relationship was symbolic
>and had a history in the OT.

Response: ACtually it is because no one is ever called son (singular) besides Christ other than Adam and that was the result of a genology,(i.e. he was fatherless so they called him son of God get it?) everyone else in the Bible are called sons (plural) of god, which denotes a lesser relatoinship.
>Of Prophet David it is written: "He shall build a house for
>My name, and I will establish the throne of his kingdom for
>ever. I will be to him for a father, and he shall be to Me
>for a son; if he commit iniquity, I will chasten him with
>the rod of men, and with the stripes of the children of
>men.” 2 Samuel 7:13-14

Response; And this verse is refering to Solomon david's actual son and find there ultimate fufillment in Christ.