What does it mean that a mediator is not of one?

The phrase 'a mediator is not of one' signifies that a mediator must represent both parties involved in a conflict. In the context of Galatians 3:20, it highlights that while God is the offended party, Christ is the mediator who serves to reconcile us to Him. This shows the profound grace of God, as He has taken the initiative to bridge the gap caused by our sin. Christ embodies both God and humanity, ensuring He effectively mediates our interests and God's holiness. This dual representation underscores the completeness of the reconciliation that Christ brings, affirming the glorious message of the gospel.