7 And yet so great are the tribulations, that even they who have trusted in Jesus, and who strive to persevere unto the end, greatly fear lest they fail; while Christ is treading the waves, and trampling down the world's ambitions and heights, the Christian is sorely afraid. Were not these things foretold him? Justly “they were afraid,” too, at seeing Jesus walking on the waves; like as Christians, though having hope in the world to come, are frequently disquieted at the crash of human affairs, when they see the loftiness of this world trampled down.
They open the Gospel, they open the Scriptures, and they find all these things there foretold; that this is the Lord's doing. He tramples down the heights of the world, that He may be glorified by the humble. Concerning whose loftiness it is foretold: “You shall destroy strongest cities,” and “the spears of the enemy have come to an end, and You have destroyed cities.” Why then are you afraid, O Christians? Christ speaks: “It is I; be not afraid.” Why are you alarmed at these things?
Why are you afraid? I have foretold these things, I do them, they must necessarily be done. “It is I; be not afraid. Therefore they would receive Him into the ship.” Recognizing Him and rejoicing, they are freed from their fears. “And immediately the ship was at the land to which they went.” There is an end made at the land; from the watery to the solid, from the agitated to the firm, from the way to the goal.
Source: Tractates on the Gospel of John (New Advent)