John Gill Commentary Zechariah 6:8

"Then cried he to me, and spake unto me, saying, Behold, they that go toward the north country have quieted my spirit in the north country." — Zechariah 6:8 (ASV)

Then cried he upon me, and spoke to me, saying
That is, the Lord of the whole earth spoke to the prophet with a loud voice, and uttered the following words: Behold, these that go toward the north country ;
meaning the Medes and Persians, which went towards Babylon: have quieted my spirit in the north country ;
by executing the judgments of God upon the Chaldeans, and by helping, favouring, and delivering the people of the Jews; which were very agreeable to the will of God, and well pleasing in his sight, signified by the quieting or refreshing his Spirit.