Paul said to the centurion and the soldiers, "Unless these men stay in the ship, you cannot be saved. (Acts 27:31)
In the Name + of Jesus. Amen. It had been revealed to St. Paul, as their ship was about to wreck, that they would all be protected by the Lord and kept safe--provided no one left the ship. So, protected by the Lord's grace, the ship broke up and everyone made it safely to shore.
But there's something else pictured here. St. Paul is the one sent by God to preach the Gospel of Christ. The ship has, since the Church's earliest days, been a symbol of the Church. To stay in the ship and be safe is another way of saying, "Stay in the church and be safe." For it is in Christ's Church that He is present by His Word and Sacraments to sustain us in the faith and bring us to everlasting life. There, in the Church, where the preacher is, Christ keeps us safe through all disasters. (And unlike St. Paul's ship, the Church can't crash and sink!)
You've known them--the kids who get confirmed and then seem to vanish from church. Perhaps you run across them in school. Maybe you ARE one of them, having drifted away from Christ and His Word and Church. Young people have lots of reasons for quitting church but most are just excuses and miss the main point: Jesus is there and it's the only place where He keeps us safe from sin and death.
Out in the world, there is no forgiveness. Nothing out there can give you peace with God--the knowledge that He doesn't count your sins against you. Nothing out there can give you the hope of everlasting life because everything out there is just fading away.
But in the Church we hear of Jesus over and over. Jesus who came for you. To carry your sins. To die and take them away. To rise and give you life. To wash you. Absolve you. Feed you. There, in the "ark" or ship of Christ's Church, sin, death, devil, hell--nothing can truly harm you.
St. Paul's plea for the passengers to stay on board the ship is a reminder to us to stay on board the ship of Christ's Church. By His grace and Holy Spirit, you will! In the Name + of Jesus. Amen.
Here stands the font before our eyes, Telling how God has received us. The altar recalls Christ's sacrifice And what His Supper here gives us. Here sound the Scriptures that proclaim Christ yesterday, today, the same And evermore, our Redeemer. (Built on the Rock, LSB 645:4)