[While Christ prays on the mountain], the ship bearing the disciples, that is, the Church, is being tossed and shaken by storms of trials and a contrary wind never calms, that is, her opponent, the devil, who is trying to keep her from reaching calm seas. But the one who is interceding for us is greater. For in this disturbance in which we are struggling, he gives us confidence, coming to us, and strengthening us so that in our confusion on the boat we don’t become so agitated that we throw ourselves into the sea. Even if the boat is being tossed about, it is still a boat. It alone bears the disciples and receives Christ. It is indeed in danger on the sea, but without it we would all perish immediately. Keep in the boat, then, and pray to God. For when all the plans of the sailors fail, when the helmsman isn’t up to it, when putting out more sails would be more dangerous than helpful, when no human help or strength is left, then all they can do is pray and call out to God. And will the God who brings sailors safely into port abandon his Church and not bring her to her rest? ....Since Peter often represents the Church, what, does it mean that Peter dared to come to Christ upon the water? What else does that statement of his mean: “Lord, if it is you, bid me come to you upon the water?” but this: “Lord, if you are truthful and never lie, may your Church be glorified in this world, because this is what was prophesied of you”? Let it walk upon the water, then, and come to you, that Church to which it was said: “The wealthy among the people will entreat your favor” (Ps 44:13). But while the Lord is not tempted by human praise, people in the Church are often disturbed by human praise and honors and are almost sinking; this is Peter wavering on the water, terrified at the great force of the storm. For who is not made fearful by that statement, “They who call you happy are deceiving you and disturbing the way of your steps” (Is 3:12)? When you are struggling against a great desire for human praise, it is good in such danger to turn to prayer and entreaty so that you who are flattered when you are praised won’t be overturned and drown when you are criticized. Let Peter as he wavers on the waves cry out, “Lord, save me!” And the Lord, while he rebukes him—“O you of little faith, why did you doubt? Why did you not keep your eye on the Lord you were seeking and stay on the right path so that you would boast only in the Lord?”—nonetheless, he stretches out his hand and snatches him from the surging waves and does not allow him to perish because he admitted his weakness and begged for the Lord’s help. When the Lord had been taken into the boat, when their faith had been confirmed and all their doubt taken away, when the seas storm had been calmed and they had reached solid and safe ground, they all adored him, saying: “Lord, you are the Son of God!” For this is eternal joy: that we know and love Truth now manifest and the Word of God and the Wisdom through whom all things were made and his surpassing mercy (Augustine, Sermon 75, 4 and 10; PL 38, 475-76, 478-79).
Look at that Peter, who symbolized us all: at one moment he trusts, at another he wavers; at one point he confesses that Christ is immortal, at another he is afraid that Christ will die. This is because the Church of Christ has some strong members and has some weak ones; and there is no Church that does not have both strong and weak members, which is why Paul the Apostle said: “We who are strong must bear the burdens of the weak” (Rm 15:1). When Peter said, “You are the Christ the Son of the living God,” he was a symbol of the strong. When he was afraid and wavered and did not want Christ to suffer, fearing his death and not discerning his life, he was a symbol of the weak. In this one Apostle, then, in Peter, the first and chief among the Apostles, the one in whom the Church is imaged, both kinds are symbolized, the strong and the weak, because you will not find a Church without both kinds (Augustine, Sermon 76, 4; PL 38, 480-81).