Redemption for the Fallen Angels?

QUESTION: Why did God not provide a scheme of redemption for the fallen angels?

ANSWER: It has not pleased God to reveal much of his dealings with the different orders of angels. We do not know that provision for the restoration of the fallen angels was not made. It is highly probable, yea, certain, that God would be as merciful to them as to the fallen human race, and that some of them failed to accept the redemptive scheme devised by him, and that many accepted it and have attained a confirmed loyalty rendering them infallible.

— Steele's Answers, pp. 230, 231.