If they refuse to take the cup from your hand and drink it, you are to tell them that this is what the LORD of Hosts says: ‘You most certainly must drink it!
KJV
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.
ASV
And it shall be, if they refuse to take the cup at thy hand to drink, then shalt thou say unto them, Thus saith Jehovah of hosts: Ye shall surely drink.