αἴτιος

Summary

αἴτιος (aitios) means "responsible, culpable, causative." As a substantive: "cause," "source," or "author." The phrase "cause/source of salvation" (αἴτιος σωτηρίας) is well-attested in Greek literature. Hebrews 5:9 applies it to Christ: "the source (aitios) of eternal salvation to all who obey him." This term is key to understanding what "source" language means in first-century Greek — and by extension what kephalē-as-source would have conveyed.

Lexical Range

LSJ — aitios: "culpable, blameworthy"; as substantive "the cause, author, origin." Used both of persons responsible for an act and of impersonal causes.

BDAG — of Christ in Heb 5:9: "cause, source" — "the pre-existent Christ is now designated as the source from whom eternal salvation flows."

Attested Usage: "Source/Cause of Salvation"

ISBE (Gloer, "Source") documents the phrase αἴτιος σωτηρίας across pre-NT literature:

• Aeschines (4th c. BC orator, Against Ctesiphon 57): the gods are "authors (aitioi) of salvation"
• Josephus (Ant. XIV.8.2 §136): of Antipater as source of deliverance
• Philo (De virtutibus 202): Noah as source of Ham's salvation
• Philo (De agricultura 96): the brazen serpent as "the source (aitios) of complete salvation" to those who beheld it
• Philo (De specialibus legibus I.252): God as source of His people's salvation
• Hebrews 5:9: Christ as "source (aitios) of eternal salvation to all who obey him"

Hebrews 5:9 ↔ Hebrews 2:10 Equivalence

Hebrews parallels aitios (5:9) with archēgos (2:10) — "originator, author, pioneer" — as designations for Christ's saving role. ISBE (Gloer): "Source in He 5:9 has practically the same meaning as archēgos in 2:10."

This establishes a semantic triangle in the NT vocabulary of source/origin: - aitios (Heb 5:9) — source, cause - archēgos (Heb 2:10; Acts 3:15; 5:31) — originator, pioneer, author - archē (Col 1:18; Rev 3:14) — beginning, source, first cause

All three communicate originative, generative agency rather than positional command. This is the semantic field Paul draws from when he calls Christ kephalē of the church (Eph 5:23, Col 1:18) — kephalē operates in this same family of source/origin terms in Pauline usage.

Application to Headship

The well-documented use of aitios for "source of salvation" shows that first-century Greek readers had ready categories for "source of life/salvation" language. When Paul calls Christ the kephalē of the church in Eph 5:23 and immediately explains "He Himself being Savior (sōtēr) of the body," he is invoking the same source-of-salvation semantic field as Heb 5:9. The kephalē saves; the husband, by analogy, loves sacrificially like the Savior (Eph 5:25-30) — not commands like a lord.

References

• ISBE, "Source" (Gloer, 4:589-590)
• LSJ, s.v. αἴτιος
• BDAG, s.v. αἴτιος
• Article 422 (ISBE compilation)