Heb.1:5 – For to which of the angels did He ever say,
“YOU ARE MY SON,
TODAY I HAVE FATHERED YOU”?
“I WILL BE A FATHER TO HIM
AND HE WILL BE A SON TO ME”?
Understanding what it means for the Father to have an only Son will take us all of eternity (which means we will never completely get it). What does it even mean, only begotten, popularized in the KJV Bible. Most modern translations have backed away from the term ‘begotten’ but that doesn’t really matter. The concept of being God’s Son implies fathering, what else could it mean? The Son of God has always been the Son of God. Before Adam and Eve, before the universe existed, and even before there was a thing we call time the Son of God has been there. He has enjoyed the beautiful relationship of love with His Father from the beginning. Here is how Andrew Murray describes what it means to be called God’s Son.
“Thou art My Son, this day have I begotten Thee. The words are used in Acts xiii. 33, of the resurrection of Christ. So the word firstborn in the next verse also has reference to the resurrection. The Son was not only begotten of the Father in eternity, but begotten again in the resurrection. In the incarnation the union between the divine and the human nature was only begun: it had to be perfected by Christ, in His human will, yielding Himself to God’s will even unto the death. In the resurrection, “He was declared to be the Son of God with power”; the full out-birth of humanity into the perfected fellowship and equality with Deity was completed; the Son of Man was begotten into all the likeness and glory of the Son of God. Thus Paul applies it : “God raised up Jesus, as also it is written in the second Psalm, Thou art My Son, this day have I begotten Thee.” He then became the first begotten from the dead.”
Something wonderful happened after the Son of God became a man. After His death, resurrection, and ascension He returned to heaven as a man. The beauty is that the Son of God is now also the Son of Man. He did all of that so that I could be called God’s son. I have received the Spirit of sonship or adoption. I have become a son of God.