Abbott-Smith Manual Greek Lexicon
Σαούλ (G4549)
9 Σαούλ , ὁ indecl. (in FlJ, Σάουλος ; Heb. שָׁאוּל ) Saul ; the King of Israel: Ac 13:21 ; the Jewish name of the Apostle Paul, used in the indecl. form only in address (cf. Σαῦλος ): Ac 9:4 , 17 22:7 , 13 26:14 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain