"This office of mediator between God and man is proper only to Christ, who is the prophet, priest, and king of the church of God; and may not be either in whole, or any part thereof, transferred from him to any other." - London Baptist Confession
Christ alone (Solus Christus, Solo Christo), is one of the five Solas of the Reformation. It emphasizes that the death and resurrection of Jesus Christ is not only necessary for salvaiton but sufficient to save to the uttermost. That no amount of human works or merit can contribute to Christ's finished priestly work. Christ’s all-sufficiency means, by implication, that we are insufficient of ourselves. Indeed the Scripture says “Not that we are adequate in ourselves to consider anything as coming from ourselves, but our adequacy is from God.” (2 Corinthians 3:5)
"I must listen to the gospel. It tells me not what I must do, but what Jesus Christ the Son of God has done for me." - Martin Luther
"The heart of the gospel is not about us. The heart of the gospel is Christ for us (Christus pro nobis). This was the essence of Paul’s message: that Christ came for us, to do for us what we could not and would not do. He obeyed. He was crucified. He was raised. He is ascended. He is returning. The medieval church turned the gospel into a message about what Christ is doing in us, by grace, in sanctification, and about what we must do to do our part in order to benefit: cooperate with grace. The good news is that we have no part, not in this story. We’re recipient. We’re beggars; we’re not contributors to the story." - R. Scott Clark
"Christ stepped in, took the punishment upon himself and bore the judgment due to sinners. With his own blood he expiated the sins which made them enemies of God and thereby satisfied him...we look to Christ alone for divine favour and fatherly love! …Hence Christ is called “King of peace” (Is. 9:6) and “our peace” (Eph 2:14) because he quiets all agitations of conscience. If we ask the means, we must come to the sacrifice by which God has been appeased. For anyone unconvinced that God is appeased by that one atonement in which Christ endured his wrath will never cease to tremble. In short, we must seek peace for ourselves solely in the anguish of Christ our Redeemer."
- John Calvin, Institutes of the Christian Religion 2.16.2