"And Peter answered Him, 'Lord, if it is you, command me to come to you on the water.'" Matt. 14:28
Here Peter demonstrates the fundamental incredulity and demand for true knowledge that real faith requires. Peter did not blindly follow anyone (except, perhaps, himself). He was not completely credulous. Listen to his own words: "Lord, if it is you...." His actions were conditional on certain facts. If it was Jesus, then He would come out onto the water. He would not go for anything else, neither ghost nor angel. Such an attitude of incredulity is common sense. Peter was a fisherman. He had sailed a boat many times. He knew what water was, that it was not a solid walking surface. The key to his actions in this verse is that he also knew who Jesus was (Matt. 16:16). Peter did not step out of the boat because he had a primitive misconception about the laws of physics. He stepped out because he had a right conception about the man called Christ. When he began to sink, and Jesus saved him and said, "Why did you doubt?" (vs. 31), the implication is that before he sank, Peter had faith, not in the sudden solidity of the water, but in the power and presence of the Son of God.
True faith has never been about blind adherence to anyone or anything. Faith is about trusting that which you know. You trust the chair that you are sitting in right now because somewhere in the back of your mind you know that either chairs in general are well-made or that your chair specifically is well-made. You trust an individual because you know that either people like them in general are good (like police officers) or that this person specifically is good (like a friend or family member). In any and all cases, faith is about trust, and trust is about some kind of knowledge in regard to the thing trusted. It may or may not be complete knowledge, but it is enough to garner trust. Likewise, the Christian life (which is a life of faith; Romans 1:17, II Cor. 5:7, & Heb. 10:38) is not about blind adherence to creeds or the mere power of an unknown God. "This is eternal life," said Jesus, meaning that here is the Christian life, "that they may know you, the only true God, and Jesus Christ whom you have sent" (John 17:3). The Christian life is about knowing God, and on that knowledge we trust Him.
-Jon Vowell (c) 2011