The Tribulation ends with the Second Coming of Christ (Rev. 19:11-21). At that time, the eyes of Israel will be opened, and all Israel will be saved (Rom. 11:25-26). They will then enter into the kingdom promised to David's Offspring (Jesus Christ). Luke wrote,
"He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto Him the throne of His father David: and He shall reign over the house of Jacob for ever; and of His kingdom there shall be no end" (Lk. 1:32-33).
For the next 1000 years, Christ will rule the earth with "a rod of iron" (Ps. 2:9; Rev. 2:27; 12:5; 19:15). During that time, children will be born, and by the end of the Millennium, the world will be mostly populated by people who only obey Christ because they are forced. That is why, when Satan is loosed for "a little season" at the end of the 1000 years, the nations turn against Christ and move to destroy Israel (Rev. 20:3-9). As the nations gather to come against Christ and His people, suddenly, fire will come down from heaven and destroy His enemies (Rev. 20:9).
The "never ending kingdom," spoken of by Luke, does not stop with the end of the Millennial reign of Christ on earth. Jesus Christ is the King of kings, and the Lord of lords forever over the new heaven and new earth (Ps. 89:36; Dan. 2:44; 7:14, 27; Mic. 4:7; Heb. 1:8; 1 Tim. 6:15; Rev. 11:15; 19:16; 22:3-5).
A good way to tell if you are a believer or not, is to think about how you feel about Christ's Second Coming; if you long for it, you are saved; if you dread it, you need to receive Christ as your Lord and Savior while there is still time!