The sea is rough; the wind is contrary; though, Jesus comes walking on the water...

The test, a sanctification of our lives by the purification of spiritual struggle.

Jesus walks upon the sea (icon from here)

Orthodox Metropolis of Zambia & Malawi

Close your eyes and try to imagine the scenery. On the grassy plain, next to the lake, there are over 5,000 people. In the background, but not far: a mountain, not too high, like all the hills around the Lake of Tiberias. On the bank of the lake stand Jesus and His disciples. On the lake, a boat; probably a simple fishing boat. It is towards the end of the afternoon; the sun is setting, but it is still very hot. Everybody has been fed from the miraculous bread; there is satisfaction; the stomach is full; the sick have been healed and the lepers cleansed; the blind see and the demons have been driven away. Silence is starting to settle. It seems that all could rest.
However, Jesus gives two commands. First, He sends the crowds away. The Greek word for “sending away” means: He delivers them from their bonds, He frees them from their chains. They are free to go. Then He turns towards His beloved disciples who usually never leave Him, and He tells them to get into the boat and go before Him on the other side. The Greek verb used here is very strong: it means “to compel somebody to do something”. The disciples evidently do not want to be separated from the Lord; nevertheless Jesus compels them to embark while He retires on the hill to pray in solitude.
Now imagine yourself on the boat trying to sail straight towards the other side of the lake. The sea is rough; the wind is contrary; you have been working hard for hours, since the evening; the night is dark; and now you almost have no strength left. It is very late, almost early morning. It is that time that when people who are close to death usually die. It is the fourth watch of the night: you no longer expect anything. Though, Jesus comes walking on the water.
You heard the story. Now open the eyes of your heart, listen with the ears of your heart, and try to understand what the Lord teaches the Church. The Fathers give us the key. The disciples represent the faithful: that is, all of us gathered here. The crowds are the God-fearing people who are not members of the Church yet. The boat is the Church. And the sea represents the world. The wind which is contrary is Satan who is trying to turn us away from our goal: the kingdom of God, i.e. the other side of the lake. The rough waves of the sea are the afflictions and tribulations, the trials and temptations which assail us during all our life. You know of course that the crossing of the lake in the boat is Christian life.
Now understand: the Lord compels us, His Church, to live in the tribulations and afflictions of this world. The prayer of Christ for His people in the Gospel of Saint John shows that we should not ask the Lord for not leading us into trials, but that we should ask Him not to let us succumb to temptations: “I do not pray that you should take them out of the world, but that you should keep them from the evil one.” Or in the Gospel of Saint Matthew: he who endures to the end shall be saved. We have no choice. Man is tested by God, and therefore the afflictions and trials are a source of joy [See: 1 Cor 10:13; James 1:2; 1 Peter 1:6; James 1:12; 1 Peter 4:12]. It is a source of joy because we are put to the test so that our faith may be purified.
Note that the test is not only educational. It is a sanctification of our lives by the purification of spiritual struggle. What do we learn through it? Before all, we learn that without Christ we are powerless. “I am the Vine ... apart from me you can do nothing.” We shall never be able to reach the other side, the Kingdom, by our own strength. In other words, it is only by a cooperation — or as the Fathers would say: a synergy [1 Cor 39 refers to us as fellow-workers of Christ] between the Lord and us that we progress in sanctity. The presence of the Spirit on the one hand, and our ascetic endeavours on the other.
We should never forget that God has never abandoned Man. He has always been working for our salvation. In the Old Testament, despite the pride of man and the just wrath of God, never did God broke the covenant. Even now, when we are sailing through the lake, apparently alone and forgotten, the Lord Jesus is present by His prayer and His intercession while in solitude on the mountain. Finally He shows at the 4th watch of the night. The Fathers explain: at the 1st watch of the night God has sent the Law to Israel; at the 2nd watch, He has sent the prophets; at the 3rd watch, He gave His Son to the world; at the 4th watch of the night, when we are ready to give up, He comes back in glory to lead us into the Kingdom. These are the four steps of His divine Mercy.
And the Lord arrives walking on the water. And when asked, he says His Name: “I am.” This has nothing to do with some of our silly modern translations using informal and casual language: “It is I.” “I am” is the Septuagint translation of the Name of God which is revealed to Moses at Sinai (Exodus 3:14). This explains the fear of the disciples: it is not only a simple fear at seeing someone walking on the water, but they are frightened at hearing the Name of God which is never used lightly, a Name that only the High Priest would pronounce only once a year in the Temple at Jerusalem.
However, Love kills fear. Peter, the chief among the Apostles, volunteers out of love for the Master to go to Him. His faith is great. But our desire to love is human and is only a pale reflection of Divine Love: Peter’s faith fails him. This limit to our faith is called doubt. Doubt may have its own positive side: it teaches us humility, it teaches us constantly that nothing is possible unless we trust fully in the Lord. Do you think that Peter walked by himself on the water because of his faith? Not at all. It is not so simple. Peter was able to walk because the Lord granted him the strength and power to do it; and because at the same time Peter hoped in the Lord. The Lord never abandons us: when Peter doubted, the Lord was still with him. If not Peter would have drowned right away. We should always remember that faith is not given once and for all. It is a constant interaction between God and Man: a constant double movement from God to Man and from Man to God.
When a man is put to the test, he is tested on his availability to God; he is tried on his ability to give himself up totally to the Lord. Such is the case of Abraham when he was asked to offer his son Isaac as a sacrifice unto the Lord. Fully abandoning ourselves in trust to God is the sign that we have passed the test.
Therefore, tomorrow when you will go through some sort of tribulation or temptation, remember the Gospel of today and say to yourself: I am sailing in the boat towards the Kingdom, the wind and the waves are rough, however the Lord is here with me: He will give me the strength if I put my hope only on Him. And then descend into the chamber of your heart and ask yourself: am I ready to say to Him the hardest words to say: Lord, I abandon myself to Thee; not my will, but Thy will.

The text of the Gospel is here.