New Defender's Study Bible Notes
3:18 once suffered. For “once suffered,” a better connotation is “once for all died.”
3:18 quickened by the spirit. “Quickened by the Spirit” means “alive in spirit.” Although His body was in the tomb, His spirit (which could be understood as essentially the Holy Spirit, who is also called the Spirit of Christ), descended “into the lower parts of the earth” (Ephesians 4:9).