John Gill Commentary Ezekiel 6:10

"And they shall know that I am Jehovah: I have not said in vain that I would do this evil unto them." — Ezekiel 6:10 (ASV)

And they shall know that I [am] the Lord
As in (Ezekiel 6:7) ; [and that] I have not said in vain ;
either within himself, in his own purposes and decrees; so the Targum, "I have not in vain decreed in my word;" or by the mouth of the prophets: that I would do this evil unto them ;
in carrying them captive, and dispersing them in other lands; for this is not the evil of sin, but the evil of punishment, or of affliction.