The Bible says that Jesus is God’s one and only son.
However, God also calls the church his children. How can we be God’s children if he has only one son?
Although the Bible is full of paradoxes – which are hard for modern people to accept but not so difficult for post-modern people and certainly not an issue for ancient people – I don’t think this is one of them.
Another truth may explain this seeming contradiction. One metaphor in understanding our relationship with God is that of a bride and groom, with Jesus being the groom and the church being the bride. Therefore, by virtue of this union, Jesus, the only son of God, brings the church into his family through marriage, thereby making us, the church, become children of God.
This is just a thought, but it’s an interesting one.