Scripturally speaking it is my opinion God wanted to expand his intimate family consisting of the Father and His Son Jesus. Angels not included since they were created and not born of God. They were, the angels, not procreated as the human family which share the blood of our father Adam.
I consider this because of the physical creation children are born everyday into which I would call the Royal Family of God. God's purpose was to give His Son siblings, and by doing so bringing many sons to glory. Here are some scriptures for my reasoning
I consider the following scriptures is more than just brotherhood
And we know that in all things God works for the good of those who love him, who have been called according to his purpose.
29 For those God foreknew he also predestined to be conformed to the likeness of his Son, that he might be the firstborn among many brothers.
30 And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified. Romans 8:28
In bringing many sons to glory, it was fitting that God, for whom and through whom everything exists, should make the author of their salvation perfect through suffering.
Hebrews 2:10
13 And again, "I will put my trust in him." And again he says, "Here am I, and the children God has given me." Hebrews 2:13
Has anyone ever heard of this theology, the net for me has not provided the name?