And the {i} bay went forth, and sought to go that they might walk to and fro through the earth: and he said, Go from here, walk to and fro through the earth. So they walked to and fro through the earth.

(i) That is, those of different colours, which ask permission, to signify that Satan has no power to hurt or afflict, until God gives it to him; Job 1:12.

Wesley's Notes

6:7 Sought to go - Waited for a commission. He said - Christ who hath all power in heaven and on earth. Through the earth - Thro' the rest of the kingdoms of the world remote from Judea, but not remote from God's wise and sovereign providence.

Jamieson-Fausset-Brown Bible Commentary

7. bay-rather, the "fleet" (or "strong"). As the "red" are not otherwise mentioned, the epithet "fleet" (as the Hebrew for "bay" ought to be translated) in Zec 6:3 seems to apply to all four, and here especially to the "red." Their office is to complete hereafter the work already in part executed by the previous three who have stilled Babylon, Medo-Persia, and Græco-Macedonia; namely, to punish finally the last great foe of Israel, the final form assumed by the fourth world kingdom, Rome, which is to continue down to the second advent of Christ. Hence they "walk to and fro through the earth," counterworking Satan's "going to and fro in the earth" (Job 1:7; 2Th 2:8, 9; 1Ti 4:1), in connection with the last awful development of the fourth world kingdom. Their "fleetness" is needed to counteract his restless activity; their red color implies the final great carnage (Eze 39:1-29; Re 19:17, 18, 21).

Matthew Henry's Concise Commentary

6:1-8 This vision may represent the ways of Providence in the government of this lower world. Whatever the providences of God about us are, as to public or private affairs, we should see them all as coming from between the mountains of brass, the immoveable counsels and decrees of God; and therefore reckon it as much our folly to quarrel with them, as it is our duty to submit to them. His providences move swiftly and strongly as chariots, but all are directed and governed by his infinite wisdom and sovereign will. The red horses signify war and bloodshed. The black, signify the dismal consequences of war, famines, pestilences, and desolations. The white, signify the return of comfort, peace, and prosperity. The mixed colour, signify events of different complexions, a day of prosperity and a day of adversity. The angels go forth as messengers of God's counsels, and ministers of his justice and mercy. And the secret motions and impulses upon the spirits of men, by which the designs of Providence are carried on, are these four spirits of the heavens, which go forth from God, and fulfil what the God of the spirits of all flesh appoints. All the events which take place in the world spring from the unchangeable counsels of the Lord, which are formed in unerring wisdom, perfect justice, truth, and goodness; and from history it is found that events happened about the period when this vision was sent to the prophet, which seem referred to therein.