And I heard how many were marked with the seal of God—144,000 were sealed from all the tribes of Israel:
A friend of mine posted on Facebook asking this question. My immediate thought was, "Oh, this is an easy one" and was about to respond to her until I read all the comments and saw all the different interpretations. So I realised that maybe it needs more research.
The way I've always interpreted the 144,000 in the Book of Revelation is the 144,000 Jews who convert to Christianity during the Tribulation. I admit I got that interpretation from the Left Behind series. It made the most sense, so I never looked into it further than that until today. I mean, the following verses literally list how they're from the twelve Tribes of Israel. Even Got Questions has this interpretation.
However, that's not the only time the 144,000 are mentioned in Revelation. Seven chapters later we get the following:
Then I saw the Lamb standing on Mount Zion, and with him were 144,000 who had his name and his Father’s name written on their foreheads. And I heard a sound from heaven like the roar of mighty ocean waves or the rolling of loud thunder. It was like the sound of many harpists playing together. This great choir sang a wonderful new song in front of the throne of God and before the four living beings and the twenty-four elders. No one could learn this song except the 144,000 who had been redeemed from the earth. They have kept themselves as pure as virgins, following the Lamb wherever he goes. They have been purchased from among the people on the earth as a special offering to God and to the Lamb. They have told no lies; they are without blame.
This time, it doesn't mention anything about them being from the tribes of Israel. Instead, it basically just sums them up as being very good followers of Jesus. Which likely is what has led to confusion.
However, what has led to further confusion is the beliefs of Jehovah's Witnesses. They believe that only 144,000 people period will go to Heaven, out of the billions of people who have lived. This is incorrect, however. As that linked article to Got Questions states:
The Jehovah’s Witnesses’ belief that they will be the only survivors of the Great Tribulation, coupled with the fact that in 2020 they numbered 8,695,808 persons in active service, clashes with Scripture’s description of a multitude “that no man can number.” The Witnesses have been numbered.
So even just that alone shows that they are incorrect.
I end this by saying I still believe what I did before, about them being converted Jews during the Tribulation. But at least I have researched it myself this time instead of going solely based on what the Left Behind series said.