Is the foundation of the church something we think up or do or say? What happens because of us and what we do, is that why the church exists? Or, to think about it another way: when we breathe and we feel it we can (to a certain degree) control our breath. But, if we don't think about breathing it goes on. We breathe whether we think about it or not. Our heart beats whether we want it to or not. The same goes for digestion, blood circulation, and how our bones take shape.
Do we or don't we control these things? We don't, do we? As much as we want to believe we can control ourselves, choose our thoughts, emotions, words, and actions, in the end, we don't have to decide to switch our brains on, or our heart, or our toes. It just happens all at once and we don't have much of a say about it either way.
In the same way, the Church of Jesus Christ is and stays Jesus' Church whether we decide it is or not. We don't decide or choose to turn Jesus on or control the movements of God’s Spirit. We don't get to decide when God enters and leaves the building, or what He does in the meantime. He just goes and does everything that makes our church the Church, all at once, for us. The Spirit gives us God's love in simple earthly words, water, bread and wine. Jesus gives Himself to us as gift in this way through these means, whether we are aware of what He's doing or not. We can pull out a microscope or blind ourselves, it doesn't matter. God will be God for us in the way of Jesus. He will be for us in the way of the Good News that He forgives and loves us. He will be for us in the way of comfort and hope, and Gospel preachers, and sacraments, and selfless love.
He does this for us all at once, everything connected underneath what we can see, smell, hear, taste, and touch. And, if that upsets us or we don't like that, well, that's just too bad. It's pointless for us to worry because we don't decide or choose how God will be God for us or how He will set up His Church to be the place where He does His Christ-Jesusing for us.
Now, if we are religious people who believe God chooses us to be the foundation of the Church and makes what we do the reason the Church exists, then this is the biggest bad news of all and it should come as no surprise to us at all that Jesus says religious people will kill those who lean entirely on Him for their every need whether it's faith needs or plain old life needs.
It should come as no surprise at all that religious people think we are offering worship to God when we kick out, banish, and even kill those deluded few who believe Jesus' faithfulness is imputed to us so we have faith. Jesus' selfless love is imputed to us so that we can love each other selflessly. Jesus' works, and ways, His suffering and death, everything that is Jesus'—even (and especially) His resurrection—is imputed to us as gift so we don't have to worry if any of that will still be here for us later today, or tomorrow, or next week, or at the minute of our death.
What do we do when God sends us a preacher to announce the Good News that the existence of the Church Jesus founded and preserves to this day doesn't depend on our doing for God and each other? We shoot the messenger, of course! We make our thinking, and talking, and our doing bigger and bigger, and all His doing for us smaller and smaller. Less Gospel, less gifts, less selfless love. In other words, more us and less Jesus.
But, that's okay. The Church exists whether we shoot the messenger or not. Jesus will still be Savior and the gifts will still be given away for free—and faith, and hope, and love will grow and thrive whether we want them to or not, because we can shoot the messenger, but we can't kill God... not again, anyways.
On the other hand, for we who cling to Jesus, who believe we must decrease and He must increase, for we who confess, "Lord, I believe, help my unbelief," here's the Good News: The foundation of the Church is the blood and water that spouted from Jesus' pierced side. The reason the Church exists is because God's Spirit sends Gospel preachers, enlightens us with His gifts, declares us "holy" and keeps us in the true faith. In His Church He daily and abundantly forgives all our sin and the sin of all believers, and on the Last Day He will raise all people from the dead and give to us and all believers in Jesus eternal life.
So, despite those who try to convince us that we are missing something by making the Church all about Jesus and His gifts, ignore them. Pay attention to the font and the altar and the pulpit. Enjoy loving each other Jesus-much. And when the religious leaders and their followers insult us, scold us, vilify us, kick us out, and even kill us... celebrate, because they did the same thing to our Lord. And remember how that turned out. Three days later He exploded out of the tomb, and since He makes us a part of that explosion, that's a gift, too. That's our destiny because we know who Jesus will be for us—or, more importantly, He knows us and He will never abandon or forsake us, and He will never kick us out of His Church.