According to Ephesians 2:19, 20, the church’s foundation is the apostles, prophets, and Jesus Christ.
I assume that you understand the significance of a foundation. If not, I’ll let Jesus explain it. At the end of his sermon on the mount, he said:
“Everyone then who hears these words of mine and does them will be like a wise man who built his house on the rock. And the rain fell, and the floods came, and the winds blew and beat on that house, but it did not fall, because it had been founded on the rock. And everyone who hears these words of mine and does not do them will be like a foolish man who built his house on the sand. And the rain fell, and the floods came, and the winds blew and beat against that house, and it fell, and great was the fall of it.” (Matthew 7:24-27)
It makes perfect sense. Doesn’t it? Since the entire structure rests on the foundation, a solid foundation gives stability to a building. A poor foundation, of course, makes the structure unstable.
More importantly, compare how Jesus described a solid foundation with what Paul says. Jesus said, “Everyone then who hears these words of mine and does them will be like a wise man who built his house on the rock” (Mt 7:24). Paul says, “You are built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone” (Eph 2:19, 20).
What is the church’s foundation? In short, it is God’s Word. The prophets, the apostles, and Jesus himself, the Word incarnate, all delivered the truth of God in one form or another. They spoke it. They wrote it. Jesus, in particular, revealed it through his person.
Let me read a paragraph from our church’s official confession of faith. The very first paragraph states:
The Holy Scripture is the only sufficient, certain, and infallible rule of all saving knowledge, faith, and obedience, although the light of nature, and the works of creation and providence do so far manifest the goodness, wisdom, and power of God, as to leave men inexcusable; yet they are not sufficient to give that knowledge of God and His will which is necessary unto salvation. Therefore it pleased the Lord at sundry times and in diversified manners to reveal Himself, and to declare His will unto His church; and afterward for the better preserving and propagating of the truth, and for the more sure establishment and comfort of the church against the corruption of the flesh, and the malice of Satan, and of the world, to commit the same wholly unto writing; which makes the Holy Scriptures to be most necessary, those former ways of God’s revealing His will unto His people being now completed. (1689 Baptist Confession)
Notice what Paul says in the next chapter as explains the mystery of Christ:
When you read this, you can perceive my insight into the mystery of Christ, which was not made known to the sons of men in other generations as it has now been revealed to his holy apostles and prophets by the Spirit. (Ephesians 3:4, 5)
You may ask, “How do we make the leap from the prophets and apostles to the written Word of God or the Bible?” Jesus didn’t describe the foundation of the church as men such as the apostles. Rather, he referred to his words or teachings. I believe Paul is implying the same here in Ephesians 2.
It’s not that God has built his church on the prophets and apostles as though they hold pope-like positions. But they were his chosen means to deliver the truth. Consequently, the words and teachings which they leave behind become the foundation of the church. As the Baptist Confession says, God’s former ways of revealing his truth have passed, making the written Scriptures necessary.
Of course, let’s not overlook the most important piece of the foundation—Christ himself. Without the right cornerstone, the foundation will not be straight and the entire structure will be unstable.
Everything in the church hinges on Jesus Christ. Our lives, our salvation, our confessions, our faith, the truth—Jesus is the cornerstone of it all. Through Isaiah, God prophesied, “Behold, I am the one who has laid as a foundation in Zion, a stone, a tested stone, a precious cornerstone, of a sure foundation” (Isa 28:16).
Notice that God did more than lay a foundation; he is the foundation. Furthermore, he is a proven cornerstone. He passes the tests required to use himself as a cornerstone. In ancient times, a builder would carefully examine stone after stone until he found the perfect rock to serve as the cornerstone. Again, without the right stone, the entire foundation will be unstable.
If Jesus and his truth are the foundation of the church, then what does that imply? What are we to assume if God is uniting us not on our personal preferences or cultural commonalities, but on the truth of his Word? It means that truth matters. The church cannot be a social club where anything goes.