Ver. 29-31. Peter, by saying if it be thou, showed that his faith was not so strong as it should have been, after he had heard his Master’s voice. By his saying to him,
bid me come unto thee on the water, he showeth a something stronger faith, and a resolution to obey his command; but his fear afterward, when the wind began to rise higher, and he began to sink, argued again the infirmity of his faith. Thus Peter is a pattern of the best believers, who though they may sometimes think that they could trust God in any state or condition, yet often mistake their own hearts, and begin to shrink in an hour of great extremity; which lets us see what need we have to pray, that God would not lead us by his providence into great temptations, much more to take heed that we do not throw ourselves into them. No man knows how he shall find his heart under a great temptation, until he hath tried it. It therefore gives us a caution, as against condemning others, so against boasting, and too much confidence as to ourselves, and lets us see how much need we have to keep our eye upon Christ and his strength in such an hour.
And immediately Jesus stretched forth his hand: God is never far off from his people when extreme troubles are hard at hand. Christ says Peter, but not without a cheek;
O thou of little faith, wherefore didst thou doubt? Doubting is directly contrary to faith, yet it will not conclude a soul to have no faith, only a little faith.