One important reason why we say that the Son is eternally begotten (eternal generation) is because this is crucial to our understanding of God as Father. Sometimes we may refer to God being the Father of creation in that he is the one who brought it into being. 1 Corinthians 8:6 says:
“6 yet for us there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist.
Note that in this verse, as with John 1, Jesus Christ, identified as the one Lord is identified as sitting on the creator side of the creator/creation distinction. Numerous commentators have observed that here, Jesus is included by Paul within the Shema, indeed, the Shema has been developed. “Hear oh Israel, there is one God” has become “Hear oh Israel, there is one God and one Lord”.
Malachi 2:1 identifies God as our Father through creation and in Colossians, Jesus is identified as the Firstborn over creation. There is a sense then in which we call God “Father”, that is how Jesus taught us to pray but our sonship is first by creation and then by adoption. Jesus alone is described as “begotten.”
So, it is the relationship between the first and second person of the Trinity which enables us to know God as Father. In Ephesians 1:3, Paul writes:
“3 Blessed be the God and Father of our Lord Jesus Christ, who has blessed us in Christ with every spiritual blessing in the heavenly places”
Our relationship to the Father, as Paul goes on to outline is in and through Christ. It is only because he is the begotten Son that we can be adopted sons, that we can call God “our Father”,
This is where it gets important. If The Son had been begotten at a specific time, whether that had been within history, at his incarnation, baptism or resurrection, or it had been at some indeterminate point of time prior to time as Arius argued, then there would have been a time when God was not Father and then a time when he became Father. There would be a sense in which God changed. An event in time, especially where the Son is in some way seen to be derived from the Father would also imply loss in God, that if the Son was derived from the Father, then that would diminish him.
Here then is one other reason as to why we insist on Eternal Generation. The Father is the Eternal Father and The Son is the Eternal Son. Now, of course Islam and others such as the Jehovah’s Witnesses will still struggle with this argument. They may choose to reject it. However, in doing so they acknowledge that it is not possible for them to know God as loving Father and so lose something from his perfections.
Faithroots 