From mesitēs (mediator). The act or office of mediation — standing between two parties to bring reconciliation. The concept is central to Christ's ongoing priestly work.
Christ's mediation is not a one-time event but an ongoing ministry. He ever lives to intercede for believers (Hebrews 7:25). His mediation is based on His once-for-all sacrifice and His present position at the Father's right hand. Unlike human mediators who eventually die, Christ holds His priesthood permanently. This gives believers eternal security and constant access to the Father through the Son.