Boncraoft, the learned Unitarian, who held to destruction, says: "We read of `eternal redemption,' [Heb. 9:12,] not that God will be forever redeeming men; but the blessed effects of redemption will be eternal. In the
same sense we may understand the punishment of eternal fire, of eternal destruction, &c.; not that the act of destroying, or the fire of consumption will be perpetual and eternal, but the effects will be. A
destruction which will never be reversed, may, with strict propriety, be called an everlasting punishment." See his Sermons. The same remarks apply to "eternal judgment." Heb. 6:2. - Death not Life, p.78.
In the language of Dr. Whitby, "This fire may be called eternal, not that the bodies of the wicked shall be ever burning in it, and never be consumed by it, since this cannot be done without a constant miracle; but
because it shall so entirely consume their bodies as that they shall never subsist again, but shall perish, and be destroyed forever by it."
"Again, with reference to the word `eternal,' we know that it
sometimes has the sense of final, or nearly that sense.
Because this destruction is eternal it does not follow that the act of destruction is to be always going on, but rather that the state of destruction is such that there is no recovery from it. Thus if a man were destroyed for a year, and then restored, it would be a punishment for a year; if for a hundred years, it would be a century of punishment; if for a thousand years, it would be a millennium of punishment - but if he was destroyed never to be restored throughout eternity, it would be an eternal punishment."