"But when the fullness of the time had come, God sent forth His Son, born of a woman, born under the law, to redeem those who were under the law, that we might receive the adoption as sons [and daughters]." (Galatians 4:4-5)
What is the Fullness of Time?
As we look at the concept of the "fullness of time," we have to remember that the Bible is God's special revelation to mankind. The pages of scripture are "God breathed." This means that God the Father, through God the Holy Spirit inspired the writers of both the Old and New Testament to faithfully record God's special revelation to us regarding His plan of redemption, along with His interaction with humanity to bring about the fulfillment of His plan of redemption. God, was able to do this because He is the sovereign Creator of the entire universe. And the salvation that Jesus brought into the world with His first coming, will reach its culmination with His second coming. In other words, the culmination of God's plan of redemption is to place all of creation under the lordship of Jesus Christ, to the glory of God the Father. Therefore, the fullness of time, was not only a date set by the Father, but it refers also to His perfect timing when the world itself was ready to receive her Messiah. At just the right time, God sent forth his Son, born of a woman, born under the law, into the world to redeem us and to make us children of God through faith alone. Prior to the incarnation of Christ, humanity was under the bondage of the law for approximately thirteen-hundred years. The law of God, was a necessary component for preparing the world for the Savior to come. The law not only showed us our sin, but it also showed us our need for a Savior, because by the law no flesh could be justified in the eyes of God. And when the law of Moses had done its work of preparing the hearts of men and women for Christ. God sent forth His Son. And Jesus the only begotten Son of God, released humanity from bondage to the Law. With the coming and the incarnation of Jesus, God fulfilled His purpose, which was both to "redeem humanity" and to "adopt" men and women into the family of God through faith alone. Moreover, when the fullness of time had come in, God accomplished two things. First He brought salvation and adoption. And secondly, He sent us His Spirit. The indwelling presence of the Holy Spirit, witnesses to our adoption as sons and daughters of God. And it's the Holy Spirit, who helps our spirit to pray as we should.
The indwelling Holy Spirit is one of the many special blessings given to all God's children through faith alone in Jesus alone. The Greek expression used by the Apostle Paul is in reference to the perfect timing of God, when He sent forth His Son. And it also covers the whole of the time between Jesus' first coming and His future return when God completes His plans for human history. And these passages from Paul's letter to the Galatians helps to convey Paul's understanding of salvation. We have to remember that salvation from both the Hebrew and Biblical vantage points, entail more than the saving of individual persons. They also encompass the redemption of the whole of God's creation. And by understanding the concept of the fullness of time, we gain a more thorough understanding that scripture foresaw God's justification of the Gentiles based on the Old Testament promises to bless the nations through Abraham. The time of the incarnation, crucifixion, and resurrection of Jesus is the time of completion. The moment in human history when God fulfilled the promises of the Old Testament. The fullness of time and the coming of Christ brought with it our redemption. A redemption that will, of course, be ultimately completed with the second coming of Christ, or when we go home to be with Jesus and we receive our glorified bodies made specifically by God to spend eternity in His presence. Therefore, it's important to understand that the fullness of time and God's sending of Christ is part of God’s gracious plan of redemption from the beginning. As the Bible tells us, "we were chosen in Christ Jesus before the foundations of the world were laid in place." In addition, the fullness of time also represents God's perfect sovereign work in the historical circumstances of the day. It was Rome's conquests that had produced the "Roman Peace" and the "Roman roads," both of which made travel safe and easy. And this political unity was built on the earlier victories of Alexander the Great, whose expansion from Greece to Egypt to India left in its wake the Greek language and culture, which became a common language throughout the empire and later made the spread of the gospel easier. Greek-speaking Jews lived in every city of the Roman Empire and the spread of the Gospel first started among the Jews in the synagogues. With the Gospel first starting in Jerusalem, then spreading to Samaria, Judea and the rest of the Roman Empire.
Davids, P. H. (1988). Fullness of Time. In Baker encyclopedia of the Bible (Vol. 1, pp. 819–820). Grand Rapids, MI: Baker Book House.
Farrell, H. K. (1996). Fullness of Time. In Evangelical dictionary of biblical theology (electronic ed., p. 279). Grand Rapids: Baker Book House.
Church, C. (2003). Fullness of Time. In C. Brand, C. Draper, A. England, S. Bond, E. R. Clendenen, & T. C. Butler (Eds.), Holman Illustrated Bible Dictionary (p. 605). Nashville, TN: Holman Bible Publishers.
Stott, J. R. W. (1986). The message of Galatians: Only one way (pp. 105–107). Leicester, England; Downer’s Grove, IL: InterVarsity Press.