A.T. Robertson Commentary Hebrews 10:39

"But we are not of them that shrink back unto perdition; but of them that have faith unto the saving of the soul." — Hebrews 10:39 (ASV)

But we (ημεις δε). In contrast to renegades who do flicker and turn back from Christ.

Of them that shrink back unto perdition (υποστολης εις απωλειαν). Predicate genitive of υποστολη, as in 12:11, from υποστελλω with same sense here, stealthy retreat in Plutarch, dissimulation in Josephus. Here alone in the N.T.

Unto the saving of the soul (εις περιποιησιν ψυχης). Old word from περιποιεω, to reserve, to preserve (Luke 17:33) to purchase (Acts 20:28). So here preserving or saving one's life as in Plato, but possession in Eph 1:14, obtaining in 1 Thessalonians 4:9. Papyri have it in sense of preservation.