he put on his outer garment ... and plunged into the sea

John 21:7
When Simon Peter heard that it was the Lord, he put on his outer garment ... and plunged into the sea

Simon Peter first responded to God's call at sea without thinking of anything else. He completely obeyed Jesus and stepped out into the sea. Soon, Peter was walking on the sea, just like Jesus, his Master did. However, soon he looked around himself, and his mind started to apply the physical restrictions that he was used to, such as man cannot walk on water. As a result he sank. For us, there are times when we are called by God and felt so empowered while doing God's task. It is important to know that once God uses us, He will continue to enable us to do greater things. Our part is to look at Him, and not look at the physical restrictions.