Although likely a twentieth century addition to the original three solae of the reformation — sola scriptura, sola fide, sola gratia — solus Christus — by/through/in Christ alone— accurately captures and reflects the message of the reformers. Solus Christus, like the other solae is designed to be set against something else. So Christ alone means that Christ’s person and work is sufficient to save sinners and there is no need for additional assistance, whether from a priest, Mary, the church, or ourselves. It suggests that Christ is all we need to be right with God. It seeks to place Christ at the center of everything. He is the one about whom sola sciptura speaks. He is the one from whom we receive grace. And he is the one in whom our faith is placed. Solus Christus means: Christ at the center.
One contemporary theologian has summarized all of this nicely,
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 recipients. We’re beggars; we’re not contributors to the story. (R. Scott Clark)
Hence Luther: “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.”
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.
As we have noted, the reformation was about cherishing the gospel. Thesis number 62 from Luther puts it this way: “The true treasure of the church is the most holy gospel or the glory and grace of God.” And at the heart of that gospel is Christ. He is the fountain of God’s grace.
The challenges of our day are different, but the call of solus Christus still remains. We must keep Christ at the center, at the center of the church’s worship, at the center of the gospel, and the center of our lives.