Black horse

This black horse's rider with the pair of balances in his hand symbolizes the rich capitalists that have a major impact on world conditions through their manipulation of national economies. Only one other verse in the Bible pictures a man with balances, or scales: "The merchant uses dishonest scales; he loves to defraud" (Hosea 12:7 NIV).
The black horse, then, represents famine and poverty perpetrated by the rich who refuse to share with those in need. The rich, on their black horse, were complicit in the last century's great wars, and their hoarding and misuse of their riches is threatening more wars and violence. The rich also, in their relentless pursuit of greater wealth, are finally succeeding in polluting the entire earth a by product of modern technology.

Another prophet, Amos, also said that the merchants the wealthy capitalists of his day who were robbing the poor instead of helping them set forth wheat, making the ephah [unit of measure] small, and the shekel [price] great, and falsifying the balances by deceit ... that swallow up the needy, even to make the poor of the land to fail" (Amos 8:46 KJV).
Oil and wine, throughout the Scriptures, symbolize abundance or luxury. The fact that the oil and wine were "hurt not" indicates a situation where wealth and luxury exist alongside famine and poverty and the gulf between rich and poor is only growing.
Ted Rudow III, MA