With God, a Son is one whom God can not only command but also teach and correct, avoiding the nuclear option used with other mighty ones. The Christ, as foretold to David, is the primary example of this Son who would build the temple rightly. Solomon was the initial fulfillment, but this established hope for an even greater fulfillment in the true Christ, the only-begotten Son. God is manifestly seen in this Son because He shows His ways through correcting, teaching, and helping this Son in all divine ways as his heavenly Father.
How does this relate to Christianity? A disciple of Christ, believing in Him and holding to His teachings, has the prospect of becoming a child of God, much like Christ is the Son of God. It is not a life of privilege. Christ taught that heavenly bliss is for those who endure terrible things in earthly life. Christ Jesus himself suffered such a degree of abandonment by God that he cried out in utter anguish on the cross. Even before this, his prayers were often anguished cries to the Father. Yet, as with Christ, a child of God receives fine-controlled correction and teaching from the Father. Through this strong interaction, the Father is manifested in them to others. Furthermore, Christ is manifested in them through their obedience to His teachings and their ongoing fellowship with Him and other disciples. This all leads to eternal life, in united fellowship with each other, with Christ, and with the Father, their God.
