The day - Either of temporal or final judgment.
It was grievous for an Israelite to part with his land. But now the seller need not mourn his loss, nor the buyer exult in him gain. All should live the pitiful lives of strangers in another country.
Related Commentaries of Ezekiel 7:12
Ezekiel 7:12
12 The time is come, the day draweth near: let not the buyer rejoice, nor the seller mourn: for wrath is upon all the multitude thereof.