How do we know preaching Christ crucified is central to salvation?

Paul declares in 1 Corinthians 1:21 that it pleased God through the foolishness of preaching to save those who believe. The message of Christ crucified encapsulates the essence of God's redemptive plan, where Jesus, the sinless Son of God, became our sin-bearer. His death and resurrection provide the only means of reconciliation to God. Without this focus, preaching would lack the power to convict and save, as the gospel rests upon the reality of Christ's substitutionary atonement. The historical event of the crucifixion is critical to understanding the full scope of God’s salvation.