four corners. The word for “corners” (Greek zonia) is translated “quarters” in Revelation 20:8, obviously referring to the four directions (note the “four winds,” one from each quarter, or quadrant, of the earth, as measured from the point of view of an observer on the surface of the earth), not to a flat, square, earth, as some critics allege.

four winds of the earth. The angels are seen as controlling the four winds; thus one is probably at each pole, the other two at opposite ends of some key equatorial diameter, restraining the winds which control the great atmospheric circulation. These winds are normally driven by the sun's heat and earth's rotation, so to keep them from blowing at all would require tremendous power. This gives a slight insight into the excelling strength of God's holy angels (Psalm 103:20). Since the atmospheric circulation is essential for continental rains, the angels will have been restraining them ever since God's two witnesses called for no rain on the earth at the beginning of the tribulation (Revelation 11:6).

nor the trees. Compare Revelation 9:4.

sealed. The “seal of the living God” (Revelation 7:2) is, in one sense, the Holy Spirit (Ephesians 1:13; 4:30) and, no doubt, this sealing ministry of the Holy Spirit will be active in respect to all who will turn to Christ during the tribulation period, including the 144,000 Israelites. Nevertheless, this seal seems to be a special physical mark of some kind, perhaps the name of Christ (note Revelation 22:4), placed on their foreheads by another mighty angel (Revelation 7:2), possibly even Christ Himself. This will assure not only their eternal life but also the preservation of their physical lives through the terrible judgments yet to come. They were to serve as God's special witnesses during the remaining years of the tribulation, especially to Israel, and possibly in the millennial age to follow. They must be especially prepared for this ministry, and therefore protected.

hundred and forty and four thousand. This is the only occurrence of the number 144,000 in the Bible, and no reason is given for it here. One possibility is that each Israelite will serve as one of the twelve tribal leaders for one month during the thousand-year kingdom age.

Juda. Juda (same as “Judah”) is placed first in the list by virtue of Jacob's prophecy following Reuben's failure as eldest son (Genesis 49:8-12; 3-7), as well as the cruelty of Simeon and Levi.

Aser. The ten tribes of the northern kingdom had been exiled to Assyria, and had never returned in any organized fashion, their genealogical records long since lost. Nevertheless God's records are intact. He will no doubt select those individuals who are to be sealed by some such process as He had used in ancient Jerusalem (Ezekiel 9:4-6).

Manasses. Note that Dan has been omitted from this list, while both Joseph and Manasseh are included. Possibly the ancient leadership of the tribe of Dan in the idolatrous apostasy of the northern kingdom had affected the spiritual characteristics of their descendants throughout the centuries, so that no Danites will be suitable candidates for this special ministry at this time (note Judges 18:1, 30-31; Amos 8:14). The tribe of Ephraim had once been the acknowledged leader of the ten tribes, but this tribe also had led in the lapse into idolatry (Hosea 4:17); perhaps this partially explains why the name of Joseph replaced Ephraim in the list instead of Manasseh. Dan, however, as well as Ephraim, will have their portions in the millennial kingdom (Ezekiel 48:1).

no man could number. Like the blood of the sacrifices under the ancient altar in the tabernacle (Leviticus 4:18), the souls of those new believers slain in these early years of the tribulation are seen as under the altar in the heavenly tabernacle (Hebrews 9:2-9).

elders. Note that both the elder and John himself are individual men. Yet, since they clearly are not a part of this great assemblage, they represent another multitude of saints who were already in heaven before this new multitude arrived there.

great tribulation. This phrase is, literally, “the tribulation, the great one.” It will follow immediately after the Antichrist has his great image, “the abomination of desolation,” set up in the new temple at Jerusalem (Matthew 24:15-16, 21; Revelation 13:6-8, 11-18). This will be the signal for the most intense of all persecutions, and a great multitude of new believers will be executed, with their souls joining those of the martyrs of the early years of the tribulation (Revelation 6:9-11) who also have “white robes” and are waiting for them.

his temple. This scene is parenthetically inserted for John's benefit between the events of the judgments of the sixth and seventh seals. It is apparently set at the end of the yet-to-come “great tribulation” (that is, the last half of the seven-year tribulation period). It does not look forward to the ultimate eternal age, when there will be no temple and there will be no night (Revelation 21:22; 22:5). Therefore, it must refer to the millennial temple of the thousand-year reign of Christ on earth (Ezekiel 43:1-7).

nor any heat. During the three-and-one-half-year reign of the Beast, there will be an intense effort to kill all Christian believers and to keep them from even buying food or drink without the mark of the Beast (Revelation 13:15-17). Their only hope of escape will be to flee to the wilderness (note Matthew 24:16; Revelation 12:14), and try to live off the land. Multitudes will die, either by the Beast's executioners or by hunger, thirst, or heat, but then they will enter into a very special realm of service in the presence of Christ.