The Hebrew noun assir means a prisoner or captive — one who is bound and held. Derived from the root asar (H631, 'to bind'), it describes both literal prisoners of war and those in confinement. The term resonates deeply in a people whose founding narrative includes slavery and captivity.
Isaiah 61:1 — 'to proclaim freedom for the captives and release from darkness for the prisoners' — is the messianic text Jesus reads aloud in Nazareth to announce His mission (Luke 4:18). God's special concern for prisoners runs throughout the Psalms.
The spiritual application is not mere metaphor: the literal truth itself points to the deeper bondage of sin and the deeper liberation only God can provide. 'The LORD sets prisoners free' (Psalm 146:7) speaks simultaneously on both registers.