The message is repeated. That day equals the whole gospel age.
How tragic for that last generation of Jews who interpreted this prophecy literally and saw the destruction of the city by the Romans and concluded that the word of God had failed. The word of God can never fail, but we can fail to understand it properly.
Many refer these verses to the last days when the Jews return to their own traditional lands and the nations of the world gang up on them. God will then deliver them. Verses 8-10 are said to describe the surrounding of Jerusalem by hostile armies and God’s vengeance on those armies at Armageddon. Some say that this has already been partially fulfilled in that Israel is now an identifiable nation, back in its own God-given territory again. Now it is in a state of unbelief, but God will work in grace and they will return to the Lord in due course.