Famine in the Tribulation

The black horse spoken of in Revelation 6:5-6 forebodes death, and the pair of balances bespeaks a careful rationing of food. Normally, a “penny” (a Roman denarius, a day’s wages in Palestine in Jesus’ day, Mt. 20:2) would buy eight measures of wheat or twenty-four of barley. Under these famine conditions the same wage will buy only one measure of wheat or three of barley.

Source: Wilmington's Guide to the Bible, quoting Charles Ryrie