Ok, let me ask it this way - Was there ever a moment in time (or eternity, if you like) that the son did not exist as a separate person from the Father? (For instance, he was inside the Father, or existed as a thought in the mind of the Father, but not as an entirely separate and different aspect of God)?
The Son is always distinct (but not separate) from the Father since He is the Son, not the Father.
The Son has always been (and therefore always
is), because He is eternal and true God. He is what His Father is and receives His eternity, deity, and everything from Him. That is what we mean when we say He is homoousios (consubstantial) with the Father, and say "Light from Light" and "God of God".
The Light of Light phrase refers to the notion that the sun has always existed with its light, that there has never been a time when the sun was not shining and giving off light. Thus as long as there has been a sun in the heavens, it has been shining and giving off light. In the same way as long as the Father has existed, He has had a Son. The Father has never been without His Son, and if the Father is without beginning, then likewise His Son is without beginning; and hence the statement in the original Creed of 325, "There was never a time when the Son was not."
The Son is
always in the Father. He is
always from the Father. He is always begotten. The Son was not begotten in time, but is eternally generated/begotten. This is outside of time. The Son is begotten of the Father
now, in the eternal present of God who is timeless and beyond time.
The Son is distinct from the Father, not separate. The Son is not an aspect of God, nor a part of God, He is God--whole and entirely. He is entirely and totally God because the Father is entirely and totally God. The Son is not the Father because He is the Son, there is actual relationship, fellowship, communion between Father and Son. This is part of the interior or ontological life of the God; the communion, the sharing, the interpenetration or perichoresis of the Three Hypostases.
And yes, the words "distinct" and "separate" are important and not just a matter of semantics, separate would indicate that they are apart (they are never apart) whereas distinct speaks of them not being identical in their fundamental personhood (e.g. the Son is always the Son, never Father and never Holy Spirit).
Additionally, the term "being" is also only used in respect to the nature of God because there is only one God. There is only one Life, one Quintessential Reality; God is a single, undivided, inseparate, non-partitioned
thing.
Being describes the most basic and fundamental concept of existence; there is only one "kind" or "type" of this existence which we call God, and it is the Ground of Being, Being-as-being. Again, this isn't simply a matter of petty semantics, but is emphasizing the importance of language so as to not confuse nor confound. It is very specific so as to communicate the appropriate understanding.
Sloppy theological articulation is, I think, one of the chief causes of theological illiteracy among Christians today, and it keeps getting repeated. It's one of the reasons why I will nitpick the heck out of something. I believe it's important that something as easily misunderstood like the Trinity should be explained rightly.
-CryptoLutheran