II. We have here the momentary triumph and swift collapse of an impure faith.
One can fancy with what hushed expectation the other apostles looked at Peter as he let himself down over the side of the ship, and his feet touched the surges and did not sink. Christ's grave, single-worded answer 'Come' barely sanctions the apostle's request. It is at most a permission, but scarcely a command, and it is permission to try, in order that Peter may learn his own weakness. He did walk on the water to go to Jesus. What kept him up? Not Christ's hand, nor any power bestowed on the apostle, but simply the exercise of Christ's will. But if he was held up by the operation of that will, why did he begin to sink? The vivid narrative tells us: 'When he saw the wind boisterous, he was afraid.' That was why. It had been blowing every bit as hard before he stepped out of the ship. The waves were not running any higher after than when he said, 'Bid me come to Thee.' But he was down amongst them, and that makes a wonderful difference. For a moment he stood, and then the peril into which he had so heedlessly thrust himself began to tell on him. Presumption subsided swiftly into fright, as it usually does, and fear began to fulfil itself, as it usually does. 'He became afraid,' and that made him heavy and he began to sink. Not because the gale was any more violent, not because the uneven pavement was any more yielding, but because he was frightened, and his faith began to falter at the close sight of the danger.
And why did the ebbing away of faith mean the withdrawal of Christ's will to keep him up? Why? Because it could not but be so. There is only one door through which Christ's upholding power gets into a man, and that is the door of the man's trust in the power; and if he shuts the door, the power stops outside. So Peter went down. The text does not tell us how far down he went. Depend upon it, it was further than over the shoes! But he went down because he began to lose his trust that Christ could hold him up; and when he lost his trust, Christ lost His power over him.
All this is a parable, carrying very plain and important lessons. We are upborne by Christ's power, and that power, working on and in our weakness, invests us with prerogatives in some measure like His own. If He can stand quiet on the heaving wave, so can His servant. 'The works that I do shall ye do also'--and 'the depths of the sea "become" a way for the ransomed to pass over.' That power is exercised on condition of our faith. As soon as faith ceases the influx of His grace is stayed. Peter, though probably he was not thinking of this incident, has put the whole philosophy of it into plain words in his own letter, when he says, 'You who are kept _by_ the power of God _through_ faith unto salvation.' He was held up as long as he believed. His belief was a hand, and that which it grasped was what held him up, and that was Christ's will and power. So we shall be held up everywhere, and in any storm, as long as, and no longer than, we set our confidence upon Him.