If Jesus is the "son of God," according to the Bible, how can He also be God?
Jesus has two integrally related natures. He shares the human nature with us and the divine nature with His Father in heaven. But, while there are many humans, there is only one God. (In fact, there cannot be multiple deities, since God is maximally great.)
It is impossible to fully compare human and divine natures. For example, Peter, James, and John, who share the human nature, are separate human beings. However, the Father, Son, and Holy Spirit, who share the divine nature, are not separate divine beings. The Father, Son, and Holy Spirit are neither a trio of gods nor equal “parts” of God. They are one.
It would also be wrong to understand that the Father, Son, and Holy Spirit are multiple personalities of a single divine person. Consider Jesus’s prayer to the Father in John 17:1–4, “Father, the hour has come; glorify your Son that your Son may glorify you. For you granted him authority over all people that he might give eternal life to all those whom you have sent. Now this is eternal life: that they know you, the only true God, and Jesus Christ, whom you have sent. I have brought you glory on earth by finishing the work you gave me to do. And now, Father, glorify me in your presence with the glory I had with you before the world began.”
With His prayer, Jesus publicly demonstrated His personal relationship with the Father, while acknowledging that He holds divine authority and shares the glory of God. Moreover, Jesus promised His disciples that “I will ask the Father, and he will give you another advocate to help you and be with you forever—the Spirit of truth.” (John 14:16–17). The Father, Son, and Holy Spirit are not the same divine person, but distinct divine persons who possess the single divine being.
The Bible gives us another helpful way to understand God’s nature by identifying Jesus as “the radiance of God’s glory” (Heb. 1:3). We know the Father by the Son, just as we see the sun by the sunlight. Light and heat, diminishing through space, transmit the power of the sun, but the Son and Holy Spirit convey the presence of God without dilution. The Son and Holy Spirit, who share in the fullness of God’s glory as distinct divine persons, reveal the eternal Father to humanity.