Then the Lamb broke open the third seal; and I heard the third living creature say, "Come!" I looked, and there was a black horse. Its rider held a pair of scales in his hand. 1
References for Revelation 6:5
I heard what sounded like a voice coming from among the four living creatures, which said, "A quart of wheat for a day's wages, and three quarts of barley for a day's wages. But do not damage the olive trees and the vineyards!"