Charles Ellicott Commentary Jeremiah 13:6

"And it came to pass after many days, that Jehovah said unto me, Arise, go to the Euphrates, and take the girdle from thence, which I commanded thee to hide there." — Jeremiah 13:6 (ASV)

After many days. — Here again the interval is undefined, but it must have been long enough (we may conjecture, perhaps, seventy days) to be an adequate symbol of the seventy years’ exile which the act of placing the girdle by Euphrates represented. So in Hosea 3:3 we have many days for the undefined duration of the exile of the Ten Tribes.