Charles Ellicott Commentary Zechariah 6:3

"and in the third chariot white horses; and in the fourth chariot grizzled strong horses." — Zechariah 6:3 (ASV)

For grisled and bay, read only the first word, grey, as in Zechariah 1:8. It is necessary (with the Syriac Version) to make this conjectural emendation. This is because (as the Hebrew text now stands), in this verse the “grisled and bay horses” are spoken of as identical, while in Zechariah 6:6-7 they are distinguished from one another. Moreover, the “red horses” are not mentioned again. Septuagint, ποικίλοι ψαροί.