In Sunday's Gospel, the Apostles get caught in heavy winds while crossing the Sea of Galilee at night in a small boat. When they see a figure walking towards them on the water, Peter challenges the figure, telling him if you are Jesus, command me to walk on the water - and Jesus tells Peter "come." You know the rest, Peter gets out of the boat, starts walking on the water - then falters, starts to sink, and is saved by Jesus.
Where the Old Testament lesson tells us about the "who" behind the kingdom of heaven through Elijah's response to what God does, the Gospel does it through Jesus' response to what Peter does. Peter gets cocky, acts before he thinks, gets scared, fails, and has to be rescued.
In a way, Peter asks for his "ready, set, fail" moment - and it's kind of funny (in a mean sort of way) to watch it happen. That Jesus doesn't laugh at him, and instead gently rescues him, tells us much about the "who" behind the kingdom of heaven.
More on Sunday's Gospel tomorrow.
Readings for the 19th Sunday in Ordinary Time: http://www.usccb.org/bible/readings/081014.cfm