The question of how one knows Christianity is right and other religions are wrong delves into matters of faith, belief, and the nature of truth itself. Within the Christian tradition, several key points are often cited to support the belief in the truth of Christianity:

1. Revelation of God in Jesus Christ: Christians believe that in Jesus Christ, God has uniquely and definitively revealed Himself to humanity. As John 1:14 states, “The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth.” The life, death, and resurrection of Jesus are seen as historical events that reveal God’s love and offer salvation to humanity.
2. Fulfillment of Prophecies: Christianity claims the fulfillment of Old Testament prophecies in the person of Jesus Christ as evidence of its truth. For example, Isaiah 53 is often cited as foretelling the suffering, death, and ultimate vindication of Jesus. Christians see these fulfillments as validating the divine inspiration of the Scriptures and the truth of the Christian message.
3. Resurrection of Jesus: The resurrection of Jesus from the dead is central to Christian belief and is presented in the New Testament as a historical event that was witnessed by many (1 Corinthians 15:3-8). Christians view the resurrection as a unique event that demonstrates Jesus’ victory over sin and death, affirming His claims to divinity and the truth of His teachings.
4. Personal Transformation: Many Christians point to the transformative power of their faith in their lives as evidence of its truth. They experience a personal relationship with God through Jesus Christ, characterized by a sense of peace, purpose, and a change in their lives that they attribute to the work of the Holy Spirit.
5. Historical Continuity and Tradition: The historical continuity of the Christian faith, preserved through the Scriptures, traditions, and teachings of the church, is also seen as evidence of its reliability and truth.

It’s important to recognize that faith in Christianity, like faith in other religions, involves belief in things not seen (Hebrews 11:1). Christians believe that faith itself is a gift from God (Ephesians 2:8-9), not simply the result of logical deduction or empirical proof. While Christians hold their faith to be true and uniquely revelatory of God’s nature and will for humanity, they are also called to engage with people of other faiths with respect, love, and humility, recognizing that discussions about religious truth are deeply personal and involve complex questions of belief, identity, and understanding.