This document summarizes a sermon about who is the greatest in the kingdom of heaven based on Matthew 18:1-14. The sermon discusses how Jesus taught his disciples that they must become like humble children to enter heaven. It also discusses how believers must not cause others, especially children, to stumble in their faith and should remove anything in their lives that could lead to sin. The sermon emphasizes that believers should welcome and care for children as they have a special place under God's protection.