If they refuse to take the cup— "If they either do not believe thy threatenings, or disregard them, because they think themselves sufficiently provided against any hostile invasion, thou shalt let them know that the judgments denounced are irreversible."
Related Commentaries of Jeremiah 25:28
Jeremiah 25:28
28 And it shall be, if they refuse to take the cup at thine hand to drink, then shalt thou say unto them, Thus saith the LORD of hosts; Ye shall certainly drink.