Clearly, this third seal pictures famine stalking the land (see Matthew 24:7; Luke 21:11). Biblically, the color black—unlike our modern conception of it as the color of evil, as opposed to white—signifies mourning and ill health as a result of scarcity (see Jeremiah 14:2; Lamentations 5:10; Nahum 2:10; all of which, in Hebrew, describe people's expressions, skins, or faces as "black" due to want). This is in keeping with another use of black or darkness in Scripture: as a sign of God's judgment for sin (Zephaniah 1:15; Joel 2:2).
The pair of scales, of course, suggests similar things, adding an economic element, as grains or other foods would often be weighed for sale. Scales could also be used, as is likely intended in the third seal, to ration food during a time of scarcity. In the vision, a denarius represents a laborer's daily wage, and a quart of grain equals a person's daily nutritional requirement. The third horseman, then, portrays a scenario of hunger and suffering, when the powers that be tightly control the meting out of staple foods at highly inflated prices.
Finally, there is the curious phrase, "do not harm the oil and the wine." Commentators have been debating the meaning of this command for centuries. It is clearly spoken by God, sitting among the four living creatures, and just as He sets the famine prices of grain, He also decrees that oil and wine be spared any harm. How are we to understand this?
Olive oil and wine are not luxury items, as many take them to be; in the Mediterranean world, they are important supporting elements of the common diet (see Deuteronomy 7:13; Hosea 2:8; Haggai 1:11; etc.). However, while they provide supplementary nutrition, people cannot subsist on them alone. Thus, they are secondary food items, and in the prophecy, they remain plentiful. This leads to two possible conclusions:
1. God is limiting the severity of famines, as "the end is not yet" (Matthew 24:6) and "these are the beginning of sorrows" (verse 8); or more likely,
2. He is indicating a measure of disparity and irregularity in these famines. Some foods will be scarce, while others are abundant. Some people will be sorely affected, while others will hardly suffer. Some areas will be hit hard, while others feel little impact.
This second conclusion suggests human involvement, a wild card in every circumstance, which would fit well with the first two seals. Unlike simple natural disasters, religious deceptions and wars require the decisions and actions of people to bring them about. God hints at a human element in all these disasters, including famine, that occur down through the centuries to remind us of our culpability in them. When man governs without the guidance of God, catastrophe and destruction are not far behind.