Every Ash Wednesday, Christians throughout the world receive the sign of the cross on their foreheads. For this one day, Christians are marked—literally—as people of the cross, which is both comforting and unsettling. The cross is the instrument of our salvation. It is also the standard of our lives, reminding us that we follow a crucified Lord who calls us to take the path of self-denial and sacrifice (Luke 9:23).

The practice of receiving the sign of the cross on the forehead has a rich history that goes beyond the Ash Wednesday ritual. When people came to faith in Christ in the early church, they entered the catechumenate—a period of instruction and preparation for baptism and full initiation into the community. Upon entering the catechumenate, the sign of the cross was traced on their foreheads, indicating their new allegiance to Christ. After completing the catechumenate, the sign of the cross was traced on their foreheads once again during baptism, this time in oil. This “sealing,” as it was called, symbolized the Holy Spirit, who united the baptized person to Christ and the church. The sign of the cross was unabashedly central to the whole process of entering the Christian life. From the outset, a Christian was marked by the cross.

From the catechumenate on, the sign of the cross on the forehead served as the defining feature of the Christian’s identity. Augustine, a bishop in the North African church, often reminded his congregation that they carried the sign of the cross invisibly on their foreheads. This spiritual sign pointed to two basic truths for Christians.

The first truth was that they belonged to Christ and his kingdom. In his Tractates on the Gospel of John, Augustine compares the sign of the cross on the forehead to the blood that was put on the houses during Passover. The blood of the lamb that marked the homes of the Israelites protected them from death and freed them from captivity (see Exodus 12). Similarly, the sign of the cross on the foreheads of Christians indicates that Christ has freed us from captivity to sin and death and brought us into his kingdom. It shows the deep union that believers have with Christ in his kingdom. Christ himself dwells within us, thereby giving us a share in his triumph over evil. Rather than being an object of shame, the cross is a token of the victory that comes to Christians by virtue of our union with Christ. To bear the mark of the cross is to affirm that our deepest allegiance is to Christ and his kingdom and that we share in the victory he achieved over sin.

The second truth pointed to by the sign of the cross is the significance of humility in Christianity. For Augustine, there is a certain fittingness to the story of salvation. Humanity fell into captivity through pride; humanity is lifted from captivity through God’s humility. The humility of God in Christ, displayed in the incarnation and crucifixion, is what saves human beings from sin and death and raises them to union with God.

This Ash Wednesday, may we remember the sign of the cross as much more than an annual ritual to begin Lent; it is an invitation to get back to the essence of the Christian life.

Yet the cross not only points to God’s humility; it also points to the humility of Christians. Augustine notes that, after Christ was born, the wise men were led to him by the sign of the star. Yet Christ did not choose a star—something high and exalted—to be the sign that would mark his followers. Instead, he chose a cross—something low and shameful in the eyes of the world. Marked by the cross, Christians are people who embrace and embody humility. For Augustine, humility (among other things) entails the recognition that salvation comes to us as a gift. It is the realization that, without the cross of Christ, we are nothing but captives to the power of sin and death. Humility is the awareness that the grace of God precedes and empowers all of our good actions and holy character. To bear the mark of the cross is to know that we have nothing that we have not received (1 Cor. 4:7) and that therefore our only glory is in the crucified Lord.

This Ash Wednesday, may we remember the sign of the cross as much more than an annual ritual to begin Lent; it is an invitation to get back to the essence of the Christian life. The cross on our foreheads summons us to live always as people of the cross. It urges us to define ourselves, above all, as people who belong to Christ and his kingdom, sharing in his victory as well as his humility.