And he saw them toiling in rowing; for the wind was contrary unto them: and about the fourth watch of the night he came unto them, walking upon the sea, and would have passed by them.
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Augustine of Hippo
AD 430
When he walked upon the waters, he seems poised to pass by them. For in what way could they have understood this, were it not that he was really proceeding in a different direction from them, as if minded to pass those persons by like strangers, who were so far from recognizing him that they took him to be a ghost? Who, however, is so obtuse as not to perceive that this bears some spiritual significance? At the same time, too, he came to the help of the men in their agitation and outcry, and said to them, “Be of good cheer, it is I; be not afraid.” What is the explanation, therefore, of his wish to bypass those persons whom nevertheless he was prepared to encourage when they were in despair? His intent in passing by them was to serve the purpose of eliciting those outcries in response to which he would then come to bring relief.
Thus the divine mercy often seems to desert the faithful in the height of tribulation, but God only acts thus, that he may try their patience, and reward them more abundantly. (Nicholas of Lyra)