How do we know that Christ is the foundation of the Church?

Christ is declared to be the foundation and cornerstone of the Church in multiple passages. In Matthew 16:18, when Jesus states, 'on this rock I will build my church,' He uses the Greek word 'Petra,' signifying an immovable rock, which points to Himself. This foundation is further affirmed in Isaiah 28:16, where He is called the 'precious cornerstone' and 'sure foundation.' The implication is that, unlike any human structure, which can falter, the Church of Christ stands firmly on His divinity and redemptive work.