Dictionary entry

τοιγαροῦν

G. Abbott-Smith's A Manual Greek Lexicon of the New Testament

τοι-γαρ-οῦν

an inferential particle,

[in LXX: Jb 22:10 24:22 (עַל־כֵּך), Si 41:16, al.;]

wherefore then, so therefore: I Th 4:8, He 12:1 (Hdt., Plat., al.).†