How do we know God's promise to build and keep His church is true?

Jesus’ declaration in Matthew 16:18, 'Upon this rock, I will build my church,' confirms God's commitment to establishing and maintaining His church. The teaching underscores that Christ, as the cornerstone, is the only foundation sufficient for church and salvation. This promise assures believers of the certainty of salvation and the endurance of Christ's church, as it is built upon divine authority, not human effort. The continued existence and spread of the church are testaments to God’s faithful work in this promise.