The Greek compound noun archiereus combines archē (first, chief) and hiereus (priest), meaning 'high priest' or 'chief priest.' It was used for the Jewish high priest who presided over the temple worship and the Sanhedrin, and — with extraordinary theological depth — for Jesus Christ in the Epistle to the Hebrews, where He is presented as the supreme and eternal High Priest.
No title captures Christ's saving work more profoundly than archiereus. Jesus is High Priest in two respects: He is both the one who offers the sacrifice and the sacrifice itself. The author of Hebrews develops this with unparalleled richness: Christ is a high priest 'after the order of Melchizedek' (5:10), whose priesthood is therefore eternal and uninterrupted (7:24–25). He made atonement not with animal blood but with His own blood, entering the true heavenly sanctuary (9:12). Most gloriously, He 'always lives to intercede' for His people (7:25) — meaning that right now, the eternal High Priest is at the Father's right hand representing every believer before God.