John Gill Commentary Ezekiel 12:10

"Say thou unto them, Thus saith the Lord Jehovah: This burden [concerneth] the prince in Jerusalem, and all the house of Israel among whom they are." — Ezekiel 12:10 (ASV)

Say you unto them, thus says the Lord God
In answer to their sneering question; or notwithstanding their stupidity and indolence, and in order to awaken them out of it: this burden [concerns] the prince in Jerusalem ;
the present reigning prince in Jerusalem, King Zedekiah. The sense is, either that that burden of goods the prophet carried out on his shoulders had a regard to the king of Judah and his captivity, and was an emblem of it; or rather that the burden of prophecy, or that sorrowful calamity predicted by the above sign or type, had relation to that prince, and would be fulfilled in him; and so the Targum,

``upon the prince is the burden of this prophecy;'' in like manner Jarchi interprets it of prophecy: and all the house of Israel which [are] among them ;
they were also concerned in it, and would be carried captive with their prince.