Note 5 at Mt 14:30: The reason that Peter began to sink was because of his fear. In Mt 14:31, Jesus used the word "doubt" in referring to Peter's fear. Fear is simply negative faith or faith in reverse (see note 1 at Lu 8:50).

Where did this fear come from? 2Ti 1:7 says, "For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind." It didn't come from God. The way that this fear was able to come upon Peter was that he took his attention off of Jesus and put it on his situation.

Fear or doubt cannot just overcome us. We have to let it in. If Peter had kept his attention on Jesus, the Author and Finisher of his faith (Heb 12:2), he wouldn't have feared. In the same way that faith comes by hearing the Word of God (Ro 10:17), fear comes by hearing or seeing something contrary to God's Word. We would not be tempted with fear or doubt if we didn't consider things that Satan uses to minister fear and doubt.

The wind and waves didn't really have anything to do with Peter walking on the water. In the natural, he couldn't have walked on the water even if it had been calm. The circumstances simply took Peter's attention off of Jesus and led him back into carnal thinking. Likewise, Satan tries to distract us with thinking about our problems. No problem is too big for God. We should cast our cares about the problems over on God (1Pe 5:7) and just keep our eyes on Jesus (Heb 12:2), the Word (Joh 1:1).

Note 6 at Mt 14:30: Peter's faith didn't fail him all at once, as can be seen by the fact that he was only "beginning" to sink. If no faith had been present, he would have sunk all at once and not gradually. This illustrates that the entrance of fear and the exit of faith doesn't happen instantly. There are always signs that this is happening. If we would turn our attention back to Jesus, as Peter did, He would save us from drowning.