The sermon explores the supremacy of Jesus Christ by analyzing Hebrews 1:9, which describes His anointing with the oil of gladness above His companions. It distinguishes between Christ's complete, unmeasured joy as fully God and the believer's increasing, measured joy as a royal priest under His mediation. The preacher emphasizes that true spiritual joy is inextricably linked to the pursuit of righteousness and the rejection of wickedness. Believers are urged to set their minds on heavenly things rather than earthly distractions to avoid grieving the Holy Spirit and diminishing their joy. Ultimately, the message calls for a life of repentance and focus on Christ, whose perfect righteousness provides the foundation for enduring spiritual gladness.