Albert Barnes Commentary Jeremiah 18:6

"O house of Israel, cannot I do with you as this potter? saith Jehovah. Behold, as the clay in the potter`s hand, so are ye in my hand, O house of Israel." — Jeremiah 18:6 (ASV)

So are ye in mine hand - When a vessel was ruined, the potter did not throw it away, but crushed it together, dashed it back upon the wheel, and began his work anew, until the clay had taken the predetermined shape. It was God’s purpose that Judaea should become the proper scene for the manifestation of the Messiah, and her sons be fit to receive the Saviour’s teaching and carry the good news to all lands. If therefore at any stage of the preparation the Jewish nation took such a course as would have frustrated this purpose of Providence, it was crushed by affliction into an unresisting mass, in which the formative process began again immediately.