How do we know the doctrine of the church's preservation is true?

The preservation of the church is rooted in the promises of Christ, particularly in Matthew 16:18, where He assures, 'I will build my church, and the gates of hell shall not prevail against it.' This indicates that, while individual congregations may falter, the universal church remains secure under Christ's lordship. God's covenantal faithfulness ensures that there will always be a remnant who are His people, who will endure in faith. In addition, Paul’s letters to the early churches stress the importance of perseverance, urging believers to stay true to the doctrines they received. The consistent presence of genuine faith across generations serves as evidence of Christ's unbreakable vow to preserve His church.