Jon Welch's sermon "Wonderbread" explores the feeding of the five thousand in the Gospel of John, focusing on Jesus' identity and provision. He highlights Jesus' testing of Philip's understanding and the importance of obedience and trust in God's abundant provision. The miracle serves as a confirmation of Jesus' identity as the unique Son of God and His care for His people. The sermon encourages surrendering needs to Jesus, trusting in His faithfulness to provide abundantly.