FIRST: The 4 Horses
and in the second chariot black horses;
and in the fourth chariot grisled (strong) and bay (spotted/speckled) horses.
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.
And the bay went forth, and sought to go that they might walk to and fro through the earth: and he said, Get you hence, walk to and fro through the earth. So they walked to and fro through the earth.
Zechariah 6:2,3,6,7
SECOND: Where's the Black Horses?
I saw by night, and behold a man riding upon a red horse,
and he stood among the myrtle trees that were in the bottom;
and white.
And the man that stood among the myrtle trees answered and said,
These are they whom the LORD hath sent to walk to and fro through the earth.
Zechariah 1:8,10
So here, in chapter 1, we have the red, white & the strong speckled horses. But not the black ones.
Here's why....the 7 churches of Revelation....
RED HORSES: Ephesus/Smyrna - 1st 2 phases of church history/heavily martryed. Notice that the red horses go nowhere-they are cut down out of the starting gate (red for blood).
BLACK HORSES: Pergamos/Thyatira - 3rd & 4th phases of church history. Polluted by the paganism of the world & eventually the control of Papal Rome (black for obvious reasons). They eventually head north (morph into Spiritual Babylon---Babylon was to the north of Israel).
WHITE HORSES: Sardis/Philadelphia - 5t & 6th phases of church history. Protestant Reformation & post Reformation movements to purify the church from Roman paganism (white for purity). But these too eventually head north (morph into spiritual Babylon).
SPECKLED/GRISLED-BAY HORSES: Laodicea - 7th final phase of church history. This chariot of people is pulled in 2 directions by these STRONG/SPECKLED HORSES..one group is pulled to & fro through the earth (think 3 Angels Message to every nation, kindred, tongue & people) while some head south (into spiritual Egypt/the world...Egypt was to the south of Israel). God's people pulled in 2 directions at the end. (Think of those who are trying to bring worldly ways in into the church, such as women ordination, evolution, emergent church mysticsim, etc.).
ANSWER: When you review what the horses represent, now you know why that in Zechariah 1, the black horses aren't part of that group.
.... the land is as the garden of Eden before them,
and behind them a desolate wilderness;
The appearance of them is as the appearance of horses;
Like the noise of chariots on the tops of mountains
shall they leap, like the noise of a flame of fire
that devoureth the stubble,
as a strong people set in battle array.
Joel 2:3-5
Are You set in Battle Array?