Abbott-Smith Manual Greek Lexicon
ἑκουσίως (G1596)
2 ἑκουσίως adv. , [in LXX: Ps 54:6 ( נְדָבָה ) II Mac 14:3 , al. ;] voluntarily, willingly : He 10:26 , I Pe 5:2 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain