Pale is χλωρός [chlōros] from which we derive chlorophyll, which denotes the green pigments found in plants. It may denote a mottled appearance, like the sorrel or dappled horses in Zechariahs vision. See Zechariahs Horses. Here it denotes the color of a person in sickness as contrasted with the appearance of health,1 for the name of the rider of the pale horse is death (θάνατος [thanatos] ).
Properly, greenish-yellow, like young grass or unripe wheat. Homer applies it to honey, and Sophocles to the sand. Generally, pale, pallid. Used of a mist, of sea-water, of a pale or bilious complexion. Thucydides uses it of the appearance of persons stricken with the plague (ii., 49). In Homer, it is used of the paleness of the face from fear, and so as directly descriptive of fear (Iliad, x., 376; xv., 4). Of olive wood (Odyssey, ix., 320, 379) of which the bark is gray.2
The word to describe the fourth horses color, chlōros (pale green), is the color of grass and other vegetation in Mark Mark 6:39 and Rev. Rev. 8:7+; Rev. 9:4+, but in the present connection, designates the yellowish green of decay, the pallor of death. It is a pale ashen color that images a face bleached because of terror. It recalls a corpse in the advanced state of corruption (Ford).3Death, and Hades followed
Death and Hades are here personified (cf. Isa. Isa. 28:18 where Death and Sheol sign a covenant). These two are often found together in Scripture for Hades is the destination of the unsaved upon passing through the gateway of death. This seems to be their relationship here because Hades followed behind Deathtaking in the soul and spirit of those who had first died. Elsewhere, the appearance of Death with Hades may denote the destination of the material and immaterial parts of man, respectively. For the body molders in the grave (death) while the spirit and soul enter the underworld (Hades). Thus, Death and Hades delivered up the dead who were in them may refer to the release of the spirit and soul of the unsaved from imprisonment in Hades to be joined with a bodily resurrection from the grave in order to stand before God in judgment (Rev. Rev. 20:13+).
The eventual casting of death and Hades into the Lake of Fire (Rev. Rev. 20:14+) may describe the total victory over these unsavory realities brought about by the cross of Jesus (Hos. Hos. 13:14; 1Cor. 1Cor. 15:21-26, 1Cor. 15:54-55; 2Ti. 2Ti. 1:10) or denote those destined for the lakethe unsaved dead whose bodies remained in the grave and souls remained in Hades until the Great White Throne Judgment. Jesus has the keys of Death and Hades. See commentary on Revelation 1:18. Death and Hades either both ride the same horse, or Death is the horseman and Hades follows on foot. In either case, the two are inseparable as Hades takes in all that Death supplies.
power was given to them
Ultimate power rests with God who allows the judgment for His purposes. See commentary on Revelation 6:2.
over a fourth of the earth
A staggering judgment when seen in relation to todays population:
If todays  world population figure of five billion is used, . . . one fourth of the earth means that Death and Hades have authority, which they apparently will exercise, to take the lives of one and a quarter billion people. The magnitude of this catastrophe can hardly be grasped because nothing comparable has happened throughout history (Swete). If limited to two continents, which it will probably not be (Beckwith; Lenski; Mounce), it will amount to the elimination of people from two of the worlds most populous ones (Walvoord).4Since Thomas wrote, the world population has risen to over 6 billion [December 2003] which would result in the death of over 1.5 billion people.5 This number would be reduced by the believers in Christ who are taken in the Rapture prior to this period.
sword. . . hunger. . . death. . . beasts
The fourfold source of judgment hints at its global scope. See Four: the Entire World, the Earth. Sword is ῥομφαίᾳ [hromphaia] : A large and broad sword, used by barbaric peoples, especially the Thracians.6 As has frequently been the case in the past, hunger follows war: the second horseman took peace from the earth and the effects of his ride contribute to the effectiveness of the fourth horseman. Although the third horseman brought great famine the greatest experienced to that timethe famine now becomes even more severe. The listing of alternative forms of death pictures inescapable judgment. Those who escape death by the sword may die of hunger. Those who survive the hunger are likely to perish from disease (death).7
Throughout human history, disease has killed people on a far more massive scale than war. More Union and Confederate soldiers died from disease during the Civil War than were killed in battle. An estimated 30 million people died during the great influenza epidemic of 1918-19 more than three times as many as the estimated 8.5 million soldiers who died in battle during World War I.8Those who survive the first three will be so weak as to be unable to defend themselves from wild beasts which will become emboldened and attack them.
So it shall be a reproach and a taunt, an instruction and an astonishment, unto the nations that are round about thee, when I shall execute judgments on thee in anger and in wrath, and in wrathful rebukes; (I, Jehovah, have spoken it;) when I shall send upon them the evil arrows of famine, that are for destruction, which I will send to destroy you: and I will increase the famine upon you, and will break your staff of bread; and I will send upon you famine and evil beasts, and they shall bereave thee; and pestilence and blood shall pass through thee; and I will bring the sword upon thee: I, Jehovah, have spoken it. (Eze. Eze. 5:15-17) [emphasis added]
Thus says the Lord GOD: Pound your fists and stamp your feet, and say, Alas, for all the evil abominations of the house of Israel! For they shall fall by the sword, by famine, and by pestilence. He who is far off shall die by the pestilence, he who is near shall fall by the sword, and he who remains and is besieged shall die by the famine. Thus will I spend My fury upon them. (Eze. Eze. 6:11-12) [emphasis added]From these passages we understand that what seem like intensified natural disturbances (war, hunger, death, attack by beasts) are in fact expressions of Gods judgment. Thus Gods wrath is already seen in the fourth sealwell in advance of the sixth and seventh seals.9
The picture being drawn is one of no escape. No matter which group or location a man finds himself in, there is a God-ordained judgment which will result in death:
For thus saith the Lord Jehovah: How much more when I send my four sore judgments upon Jerusalem, the sword, and the famine, and the evil beasts, and the pestilence, to cut off from it man and beast! (Eze. Eze. 14:21) [emphasis added]
Thus shalt thou say unto them, Thus saith the Lord Jehovah: As I live, surely they that are in the waste places shall fall by the sword; and him that is in the open field will I give to the beasts to be devoured; and they that are in the strongholds and in the caves shall die of the pestilence. (Eze. Eze. 33:27) [emphasis added]Amos predicted this character of the day of Jehovah: Woe unto you that desire the day of Jehovah! Wherefore would ye have the day of Jehovah? It is darkness, and not light. As if a man did flee from a lion, and a bear met him; or went into the house and leaned his hand on the wall, and a serpent bit him. Shall not the day of Jehovah be darkness, and not light? even very dark, and no brightness in it? (Amos Amos 5:18-20).
There is intentional irony in Gods reversal of roles as men become the source of food for beasts (Gen. Gen. 9:2-3 cf. Eze. Eze. 29:5; Eze. 39:17-20; Rev. Rev. 19:17-18+). When man is disobedient to God, He reverses the original divine order where man was given dominion over the beasts (Gen. Gen. 1:26-28; Gen. 9:2-3) and gives man into the hand of beasts (Lev. Lev. 26:22; Deu. Deu. 32:24). The beasts will be emboldened both because of the emaciated and sickly condition of men and the scarceness of their own food supply. Once food becomes scarce, wild animals which generally leave man alone will begin to attack man for food.10
1 Frederick William Danker and Walter Bauer, A Greek-English Lexicon of the New Testament and Other Early Christian Literature (Chicago, IL: University of Chicago Press, 2000), 882.
7 Metonymy of the Effect, the effect (death) put for the cause producing it (pestilence).Jerome Smith, The New Treasury of Scripture Knowledge (Nashville, TN: Thomas Nelson Publishers, 1992), Rev. 6:8.
8 John MacArthur, Revelation 1-11 : The MacArthur New Testament Commentary (Chicago, IL: Moody Press, 1999), Rev. 6:8.
9 The context of Ezekiel Eze. 5:17 (Eze. Eze. 5:12-16) indicates that the famine, beasts, pestilence, and sword of that passage are expressions of Gods wrath.Renald E. Showers, Maranatha, Our Lord Come (Bellmawr, NJ: The Friends of Israel Gospel Ministry, 1995), 115.