Jesus’ disciples were very much concerned with the restoration of the kingdom to Israel (Acts 1:6). While we do not know all the reasons why Christ did not consummate His kingdom two thousand years ago, we do see that the time between His two advents has allowed for many nations to join His people Israel. Thank God for the merciful inclusion of the Gentiles and seek to support the missions activities of your church that proclaim His reign over all men.
The existence of the church is not a “plan b” that God turned to when “plan a” did not work out. Instead, the church is the goal toward which the Lord has been working from the beginning. A church made up of people from all around the world is a fulfillment of prophecy and a striking proof of the truth of Scripture. When tempted to discouragement, we should look at the church’s growth throughout history as a proof that the Lord is working out His plan.