Those who do not fully understand the Holy Bible and those who refuse to understand it, often ask how Jesus could possibly have been God, and yet have been the Son of God. It is a good and legitimate question for those who desire to understand it but those who refuse, will never understand it.
Admittedly, the concept is difficult to understand by physical human beings simply because we cannot conceive of life in the spirit without the fleshly body. We are physical and none have had experience out of the body even though many profess to have had such. But once we can begin to understand that God is a spirit (John 4:24).
A spirit is not physical in any respect. True, they can manifest themselves as a physical human, a cloud, a burning bush, or presumably any physical item which they desire. They can even enter into a human (e.g., the Holy Spirit in Acts 2)
With that understanding, let us consider some things. The Almighty God consists of three entities. The Father, the Son and the Holy Spirit. Since a spirit is a mentality, it is possible for three such spirits to have equal capacities. The three in the Godhead, have total power, total wisdom and knowledge and all are unrestricted by space, meaning they are omnipresent. Therefore, since all three know all things, there is no room for even the slightest disagreement...so they are one. In complete accord.
Before the creation of our universe, the Godhead three held a counsel and determined to create the universe and mankind. It was determined at that meeting which entity would have a certain part in the plan for man and his salvation from sin. (Acts 2:23)
The above explanations do not yet explain how Jesus could be God as well as the Son of God. But we must understand, in order to become a human and be subject to human desires, pains, and all other factors which cause man to sin, Jesus had to be born of a human and thereby inherit all of those factors. So, once the Holy Spirit came upon Mary and she conceived, the Spirit of Jesus was confined to that human. This is the means whereby He became 100% human and 100% God. The God-Spirit was within Him, yet he was born of a human.
Jesus became the "only begotten Son" of God. Jesus, who walked upon the earth among the Israelites, was truly the Son of God by having been begotten of the Father. Yet, the Spirit within Him, was God...a part of the Godhead.
Another factor which may help to understand is that the expression "the son of" is often used concerning people who have certain characteristics. James and John, sons of Zebedee, were called, "sons of thunder" because of their nature in Mark 3:17. Paul referred to
Elymas the sorcerer as "the child of the devil" in the King James Version, but it is translated as "son of the devil" in the New King James and others. So, Jesus not only had the right to be called the Son of God, since He truly was, but also since He had the characteristics of God.
As His time on earth drew near to its close, Jesus prayed this prayer to God the Father:
These words spake Jesus, and lifted up his eyes to heaven, and said, Father, the hour is come; glorify thy Son, that thy Son also may glorify thee: As thou hast given him power over all flesh, that he should give eternal life to as many as thou hast given him. And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent. I have glorified thee on the earth: I have finished the work which thou gavest me to do. And now, O Father, glorify thou me with thine own self with the glory which I had with thee before the world was. (John 17:1-5 KJV)