Charles Ellicott Commentary Zechariah 5:6

"And I said, What is it? And he said, This is the ephah that goeth forth. He said moreover, This is their appearance in all the land" — Zechariah 5:6 (ASV)

What is it? —that is, What does it symbolize? For, of course, he could see that it was an ephah.

This is an ephah ... all the earth. —Better, This, the ephah that comes forth, this, he continued, is their resemblance throughout all the lands: that is, this is a symbol of the sinners mentioned above. (For “resemblance” the Septuagint, by the change of one letter, read iniquity.)

The nature of the comparison is seen by some to be as follows: As in an ephah the separate grains are all collected together, so the individual sinners over the whole length and breadth of the land will be brought into one confused heap. (Compare Matthew 13:30.)

It is not mentioned until later that they are to be carried away.