Hurter observes that St. Ambrose understands mortality in a wide sense, as including the capacity of any and every sort of change. Immortality, then, in accordance with this definition, would connote perfect absence of change. Hurter cites St. Bernard, § 81 in Cant.: “Omnis mutatio quædam mortis imitatio…Si tot mortes quot mutationes, ubi immortalitas?” and Plutarch, in Eusebius, Præpar. Ev. XI. 12. Plutarch’s view perhaps owed something to study of the reliques of Herachtus. Many fathers expounded 1 Tim. vi. 16 on this definition of immortality as=immutability. This definition would exclude angels, who are naturally fallible (as the rebellion of Lucifer and the third part of the host of heaven proved)—or if they are now no longer fallible, they owe it not to their own natural constitution but to grace. In so far then as angels are mutable, whether for better or worse, they are not immortal.