The manner of the answer is noteworthy. It is determined by, and adapted to, his weak faith. He could not be upheld now as he had been a moment ago, before his fear had weighted him, by the exercise of Christ's will only. Then Christ could hold him up without touching him, but now the palpable grasp of the hand was needed to assure the tremulous, doubting heart. So we, too, sometimes need and get material and outward signs which make it easier to feel the reality of sustaining grace. But whether we do or no, Christ's swift help always takes the form best suited to our faith, and He has regard to the capacity of our clasping hands in the measure and manner of His gifts.
The time and tone of Christ's gentle remonstrance are remarkable. Deliverance comes first, and rebuke afterwards. Having first shown him, by the fact of safety, that his doubts were irrational, Christ then, and not till then, puts His gentle question. Perhaps there was a smile on His face, as surely there was love in His voice, that softened the rebuke and went to Peter's heart.
What does Christ rebuke him for? Getting out of the boat? No. He does not blame him for venturing too much, but for trusting too little. He does not blame him for attempting something beyond his strength, but for not holding fast the beginning of his confidence firm unto the end. And so the lesson for us is, that we cannot expect too much if we expect it perseveringly. We cannot set our conceptions of Christ's possible help to us too high if only we keep at the height to which we once have set them, and are assured that He will hold us up when we are down amongst the weltering waves, as we fancied ourselves to be when we were sitting in the boat wishing to be with Him. That is the question that He will meet us with when we get up on the shore yonder; and we shall not have any more to say for ourselves, in vindication of our tremulous trust, than Peter, silenced for once, had to say on this occasion.
It will be good for us all if, like this apostle, our trials consolidate our characters, and out of the shifting, fluctuating, impetuous nature that was blown about like sand by every gust of emotion there be made, by the pressure of responsibility and trial, and experience of our own unreliableness, the 'Rock' of a stable character, steadfast and unmovable, with calm resolution and fixed faith, on which the Great Architect can build some portion of His great temple.