The Good News Translation of Galatians 4:4-5 reads like this: “When the right time finally came, God sent his own Son. He came as the son of a human mother and lived under the Jewish Law, to redeem those who were under the Law, so that we might become God’s children.”
The “right time” refers to the perfect time in history. When history was ripe and ready for the Incarnation. Notice that Jesus was born at the exact time when there was peace throughout the Mediterranean world during the Pax Romana- the Roman Peace. It was the time when there was one universal language spoken, because, just generations before, Alexander the Great had conquered the Mediterranean world and beyond, spreading his native language, Greek. It was the time when the Pharisees were the most influential Jewish sect, a group who would spearhead the crucifixion of Jesus. It was the time when there was a network of well-built Roman roads upon which people were able to carry the gospel message throughout the Roman world.
Good roads, one language, peace for safe and open travel, and a group of opponents who would make sure that Jesus went to the cross. It was into THAT geo-political, cultural, historic context that Jesus was born. It was perfect timing—all according to God’s plan.