How do we know the Gospel is the only true message?

The Apostle Paul emphasized that he was sent not to baptize but to preach the Gospel (1 Corinthians 1:17), illustrating that the core of Christianity lies in this singular message. This Gospel must be proclaimed without human wisdom or modification, for it is through the unadulterated truth of Scripture that God brings people to salvation. If the message preached does not align with the biblical Gospel, it is not the true Gospel. Thus, the truth of the Gospel stands as the foundation of faith among believers, affirming its unique role in God's plan for redemption.