Only here and Heb 6:16. The kindred verb βεβαιόω to confirm, occurs frequently, as Rom 15:8; 1Co 1:8, etc.
Partakers of my grace (συγκοινωνούς μοῦ τῆς χάριτος)
Better, as Rev., partakers with me of grace. Lit., the grace, either the divine endowment which enabled them both to suffer bonds, and to defend and establish the Gospel, or the loving favor of God, which confers suffering and activity alike as a boon. The two may be combined. Compare Phi 1:29.