For the purpose of making humanity into Sons of God, the First and Second Comings of Christ are called ‘Sending Forths’ – “that to the nations, the blessing of Abraham may come in Christ Jesus, that the promise of the Spirit we may receive through the faith.” (Galatians 3:14)
The Cross gave us authority to become Sons of God
According to the Apostle, the First Sending Forth (Coming) was when “God sent forth His Son, having been born of a woman, having been born under the Torah, that He might redeem those under the Torah, so that we might receive the divine adoption as sons.” (Galatians 4:4-5)
Israel had been under the jurisdiction of the Torah. Its people were under its curse for not obeying every single jot and tittle. The Apostle shows Israel’s pivotal role in mankind’s salvation. God first had to save Israel so that the way of becoming divine sons of God could be opened to humanity.
As a result of the First Coming, the way was prepared for mankind, by faith in the Son of God, to have “authority to become the sons of God, even to them that believe on his name.” (John 1:12)
The Second Coming facilitated the Spirit Birth of the Sons of God
When the salvation of Israel was secured at the cross, then the Second Sending Forth (Coming) began. The Apostle wrote, “And because you are sons, God sent forth the Spirit of His Son into our hearts, crying out, ‘Abba, Father!’” (Galatians 4:6)
This Second Sending Forth began on the day of Pentecost, and has continued since.
As a result of the spirit of the Son of God being sent forth into the hearts of believers, “you have received the Spirit of divine adoption as sons, by whom we cry, ‘Abba! Father!’ The Spirit Himself bears witness with our spirit that we are children of God.” (Romans 8:15-16)
This new birth moves the believer from the old Master/Slave relationship, into a new Father/Son relationship with God. The Apostle wrote, “So you are no longer a slave but a son; and if a son, also an heir through God.” (Galatians 4:7)