There is a common misconception that only 144,000 people are going to Heaven. This is not true. The Bible does not make it clear how many people will make it to Heaven. Jesus Christ states that there are many dwelling places in Heaven (John 14:2). Since our God, Jehovah, is so big that the Earth is his footstool, it is only right to believe that Heaven is too big to only have only 144,000 residents from Earth living there (Isaiah 66:1).
The New Jerusalem
However the Bible gives us specific measurements of the New Jerusalem. The city was laid out like a square, as long as it was wide. He measured the city with the rod and found it to be 12,000 stadia in length, and as wide and high as it is long. The angel measured the wall using human measurement, and it was 144 cubits thick. – Revelation 21:16-17.
12,000 stadia = 1380 miles
144 cubits = 126 feet
This is how big the holy city is comparing to the size of the Earth. This means that the buildings of the new Jerusalem would be over 600,000 stories tall, making this the biggest city in the world. This city can fit 53 trillion people if everyone had a 1000 sq home. According to PRB, there has been over 108 billion people who have ever lived on Earth.
Where did some get 144,000 from?
In the Book of Revelation is the only place that mentions 144,000 people who are sealed in Israel. Chapter 7 and 14 of the Book of Revelation explains in detail who are these people. These are virgin male Messianic Jews whom Christ chooses to stand beside him on Mt. Zion (Revelation 7:4, Revelation 14:1-5). In Heaven, John also saw countless people who were survivors of the great tribulation putting on robes and celebrating (Revelation 7:9-17). These people are not the 144,000 from different tribes of Israel but people who will go through persecution for their Christian faith around the world.
So have no fear, our fellow Christians, if you live a life pursing a relationship with Jesus Christ, you will make it in Heaven. Knowing Jesus Christ himself is the only way we can have eternal life (John 14:6). This is why Jesus Christ states that not everyone who calls on him will go to Heaven but the ones who know him and the will of the father in Heaven (Matthew 7:21-23).