“The black horses which are therein go forth into the north country; and the white go forth after them; and the grisled go forth toward the south country.”
King James Version (KJV)
6:6 The black horses - The angels signified by the black horses are the executioners of God's just displeasure. Therein - In the second chariot. The north - country - Babylon. The grisled - The angels signified by these, managed the Roman power, which was sometimes favourable, sometimes fierce and severe, to those they had to do with. The south - country - Egypt and Arabia, which lay south of Judea. It may perhaps point at their invading Africa too, whose punishments were mixed, with kindness and mercy more than the punishments of Babylon were.