2500 years ago and 700 years before Jesus was born, God spoke through the prophet, Isaiah, and said: " And in that day there shall be a root of Jesse, which shall stand for an ensign of the people; to it shall the Gentiles seek: and his rest shall be glorious." (Isaiah 11:10)
Jesse was the father of David and Jesus was a descendant of David. So this is speaking of Jesus coming to earth. Even Gentiles will seek Him and as the prophecy states, "his rest shall be glorious".
Here is another important fact. The six-pointed star was the crest, or symbol, of the family of Jesse. We know it today as the Star of David, which is the symbol of Israel. The word for flag in Hebrew is "ensign".
On October 28, 1948, five months after the nation of Israel was established, it adopted the Star of David to be put on its flag. So, the prophecy given by Isaiah 2500 years ago came true. Jesus was born and although the people of Israel were dispersed throughout the earth, God brought them back to the land as it was prophesied. Shortly after, they adopted the Star of David as their symbol and put it on their ensign, or flag, just as Isaiah 11:10 said would happen.