Galatians 3 and 4 explains how God sought to lay a foundation for the coming of the Messiah, through the Jewish Law. The Law was to make people understand the depth of their sinfulness (in that they were incapable of keeping the Law) so that they might more readily accept the cure for that sin through Jesus the Messiah (Galatians 3:22-23; Romans 3:19-20).
So God was making His chosen people ready for the arrival of Messiah and we read in
“But when the time had fully come, God sent his Son, born of a woman, born under law”.
This verse declares that God the Father sent His Son when “the time had fully come.”
Finally, Christ came in fulfillment of specific prophecy. Daniel 9:24-27 speaks:
“Seventy weeks have been determined concerning your people and your holy city to put an end to rebellion,
to bring sin to completion, to atone for iniquity, to bring in perpetual righteousness, to seal up the prophetic vision,
and to anoint a most holy place. So know and understand: From the issuing of the command to restore and rebuild Jerusalem until an anointed one, a prince arrives, there will be a period of seven weeks and sixty-two weeks. It will again be built, with plaza and moat, but in distressful times. Now after the sixty-two weeks,
an anointed one will be cut off and have nothing. As for the city and the sanctuary, the people of the coming prince will destroy them. But his end will come speedily like a flood. Until the end of the war that has been decreed there will be destruction. He will confirm a covenant with many for one week. But in the middle of that week he will bring sacrifices and offerings to a halt. On the wing of abominations will come one who destroys, until the decreed end is poured out on the one who destroys.”
Whether anyone is able to decipher this timetable or not, but it is believed that this prophecy recorded by Daniel over five hundred years beforehand is for arrival of Christ.
Looking from men’s perspective, that particular point in history was a good time for Christ to come. There were many things occurring at the time of the first century. At least by human reasoning, the time seem to be ideal for Christ to come then.
There was a great anticipation among the Jews of that time that the Messiah would come as the Roman rule over Israel had made the Jews hungry for the Messiah’s coming.
Rome had unified much of the world under its government, giving a sense of unity to the various lands. The empire was relatively peaceful, travel was possible, allowing the early Christians to spread the gospel. Such freedom to travel would have been impossible in other eras.
While Rome had conquered militarily, Greece had conquered culturally. A “common” form of the Greek language was the trade language and was spoken throughout the empire, making it possible to communicate the gospel to many different people groups through one common language.