NOTES for Rev 7:4
By the end of time the process of forming the people of God is also completed. The 144 thousand chosen symbolize it. This number is symbolic: 12 thousand people from each of the twelve tribes of Israel. Israel here evidently means the people of God as a whole, but the people in its history, just as Israel itself exists within world history.
Since the expression 'thousands of Israel,' among other things, in biblical language means the fullness of Israel as the people of God, the 144 thousand of the Book of Revelation, where there are twelve of these 'thousands' from each tribe, signify a kind of 'fullness of fullness,' the absolute fullness of the people including all its generations throughout earthly history. This is not surprising: the issue is the history of the world that has already come into contact with the Kingdom, or more precisely, the history of the Kingdom entering the world, where no one disappears, goes into the world of shadows, or is lost.
The fullness of the people of God is the fullness not only of all historical spaces, but also of all historical times. That is why the 144 thousand include representatives not only of the Jewish people, not only descendants of Abraham by blood, but also his descendants by spirit, seekers of God and the Kingdom from all times and peoples. Of course, with a person's spiritual life and spiritual path, not everything is so simple.
Even regarding those who belong to the people of God in its history, nothing can be said with certainty. The apostle is shown the picture of the end of time, the completion of history, when everyone has already finished his path and therefore has spiritually determined himself. He does not see how many people, perhaps formally belonging to those who in history were called chosen, finally did not enter the number of the chosen. John sees those who reached the end, but does not see those who did not reach the end. And the 144 thousand revealed to him were determined and formed only there where he sees them, at the threshold of the Kingdom. There, where everything is decided and everything is determined.