Revelation 7:1-17 – The 144,000
This section is an interlude between the 6th and 7th Seals. This is the first of three interludes (the following are found in 10:1-11 and 20:1-6 explaining the place of the saints in the events of Revelation. (As with the Egyptian plagues, the seals, trumpets, and bowls relate only to sinners.)
Literal and symbolic approaches differ sharply in interpreting the vision of the “144,000, sealed from every tribe of the sons of Israel” (7:4) and its relation to the next vision of an innumerable multitude “from every nation” (v. 9).
Many understand this to be a reference to ethnic (or biological) Israel, and they would view the 144,000 as a symbolic or actual number of Jewish believers brought to faith immediately after Jesus returns and removes the church from the earth before (or during) a seven-year tribulation (this is a “pretribulation rapture” view).
However, another common approach understands “Israel” as a reference to the church, the new covenant people of God, and in this view the visions of the 144,000 and of the international multitude are complementary perspectives on the church, believers from every nation including ethnic Israel. They are protected from the Lamb’s wrath as his own flock (v. 17) but are exposed to persecution by evil enemies. The 144,000 reappear in 14:1–4, and their description there has a bearing on the interpretation here.
Source: ESV Study Bible Notes