Dear ExMilitary.
So, I'm not sure what it is you are actually trying to communicate. Regardless of what anyone else may or may not have known at the time, Was Jesus the only begotten Son of God at His birth or not?
The answer to your question above is, in my humble opinion, no. I now realize what it is that is confusing you. Part of the blame rests with me. I never denied that Jesus was the only begotten Son of God, I just do not think that this term is speaking of either the conception or birth of Jesus, the Son of man. You, however, do. I think that Jesus was thought of as being this because of his resurrection, not his birth: although it would be quite natural to assume that the term 'the only begotten Son of God' had something to do with his birth. There are scriptures that support this. You and I view the Lord Jesus Christ in two different ways. While you assume that Jesus and the Word of God are identical, I treat them both as two separate beings. Trinitarians, like I said in another post, view the Messiah as being one person with two natures, the person being the Word of God. I do not. You give me the impression that you are confusing the two natures by making no distinction between them whatsoever. Jesus is for you both human and divine. To Trinitarians it is the Word of God that has a human nature and also one that is divine. I agree with this statement but I reject their assumption that only one person was present in the human body of Jesus, being the Word of God. From my understanding of Holy Scripture Jesus had his own human personality, which was quite evident on occasions. If he did not then he would not be for me fully man, as the Trinitarians like to call him.
This is where I am confused. What is the purpose of the distinction are you making between the following:
1. Being the only begotten Son of God from conception (as you've indicated in the above quotation)
2. Having the Father declare this, from heaven, during His baptism.
You are very observant concerning this matter. There is a difference to me concerning these two incidences. The difference is that they are not relating to one and the same person, as you might think, but to the Word of God and Jesus. The Word of God became the Son of God the moment He was a part of humanity. No human being could ever obtain to the perfect righteousness of the Law of God by his own obedience. However, that is what was required of him before he could have fellowship with God. The Word of God could not obtain this righteousness, on our behalf, by His obedience to the Law of God because He was never subject to the Law of God as humans are. Therefore, the Word of God needed a human body to accomplish this.
Wherefore when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me: Then said I, Lo, I come (in the volume of the book it is written of me,) to do thy will, O God. Heb 10: 5 & 7
Then said I, Lo, I come: in the volume of the book [it is] written of me, I delight to do thy will, O my God: yea, thy law [is] within my heart. Psalm 40: 7 & 8
According to Psalm 40 the Word of God was performing the will of God by keeping the Law of God with the body that had His law in his heart, namely Jesus. This was also necessary so that the Body of our Lord and Saviour Jesus Christ was without blemish and therefore acceptable to God as a sacrifice, in accordance with His Law.
The second reference was to Jesus, the Son of man, who was appointed by God to be that descendant of King David who would be the rightful heir to the throne of his father David, which God promised King David to give to him. The angel Gabriel confirmed this in his conversation with Mary. To the Jews this King would be called the Son of God because of what God said to David about him in the covenant that God made with David.
And it shall come to pass, when thy days be expired that thou must go to be with thy fathers, that I will raise up thy seed after thee, which shall be of thy sons; and I will establish his kingdom. He shall build me an house, and I will establish his throne for ever. I will be his father, and he shall be my son: and I will not take my mercy away from him, as I took it from him that was before thee: But I will settle him in mine house and in my kingdom for ever: and his throne shall be established for evermore. According to all these words, and according to all this vision, so did Nathan speak unto David. 1 Chronicles 17: 11 - 15.
Since God said to David, "I will be his father, and he shall be my son.", then his descendant would be called the Son of God. After Jesus was baptized God the Father called him 'my beloved Son' in the presence of John the Baptist. This was God's way of confirming that Jesus was the descendant of David that would be the eternal King over the house of Jacob. This is why Jesus, as a man, was called the Son of God.
The Word of God was called the Son of God for a different reason than Jesus was called that. However, they both had the one goal before them, which was to save the elect and make them citizens of the Kingdom of God.
Would this not make Him:
1. Begotten
2. The son of God
3. The only one that meets #1 and #2
Hence, the only begotten Son of God..?
Jesus was called 'only begotten' not because of his unique conception or birth but because he was the only one acceptable to God as King of His Kingdom. God called Isaac 'your only son' when speaking to Abraham, but he was not the only son of Abraham. God knew this, of course, but He meant that Isaac, and his descendants, was the only one who had the right to inherit the land that God wanted to give to Abraham. Both these terms had nothing to do with birth in the sight of God.
Thank you for your perseverance and I do hope that I have managed to clear up any misunderstanding that has arisen about this matter. It is very hard to understand.