From: John 14:27-31a
The Promise of the Holy Spirit (Continuation)
(Jesus said to His disciples,)  "Peace I leave with you; My peace I give to you; not as the world gives do I give to you. Let not your earts be troubled, neither let them be afraid.  You have heard Me say to you, `I go away, and I will come to you.' If you loved Me, you would have rejoiced, because I go to the Father; for the Father is greater than I.  And now I have told you before it takes place, so that when it does take place, you may believe.  I will no longer talk much to you, for the ruler of this world is coming. He has no power over Me; [31a] but I do as the Father has commanded Me."
27. Wishing a person peace was, and still is, the usual form of greeting among Jews and Arabs. It is the greeting Jesus used, and which the Apostles continued to use, as we can see from their letters (cf. 1 Peter 1:3; 3 John 15; Romans 1:7; etc.). The Church still uses it in the liturgy: for example, before Communion the celebrant wishes those present peace, a condition for worthily sharing in the holy sacrifice (cf. Matthew 5:23) and also a fruit of that sacrifice.
On our Lord's lips this common greeting acquires its deepest meaning; peace is one of the great messianic gifts (cf. Isaiah 9:7; 48:18; Micah 5:5; Matthew 10:22; Luke 2:14; 19:38). The peace which Jesus gives us completely transcends the peace of the world, which can be superficial and misleading and compatible with injustice. The peace of Christ is, above all, reconciliation with God and reconciliation of men with one another; it is one of the fruits of the Holy Spirit (cf. Galatians 5:22-23); it is "serenity of mind, tranquility of soul, simplicity of heart, a bond of love, a union of charity: no one can inherit God if he does not keep His testament of peace, or live in unity with Christ if he is separated from Christianity" (St. Augustine, "De Verbis Domini Serm.", 58).
"Christ `is our peace' (Ephesians 2:14). And today and forever He repeats to us: `My peace I give to you, My peace I leave with you'. [...] Never before in the history of mankind has peace been so much talked about and so ardently desired as in our day. [...] And yet again and again, one can see how peace is undermined and destroyed. [...] Peace is the result of many converging attitudes and realities; it is the product of moral concerns, of ethical principles based on the Gospel message and fortified by it. [...] In his message for the 1971 Day of Peace, my revered predecessor, that pilgrim of peace, [Pope] Paul VI, said: "True peace must be founded upon justice, upon a sense of the untouchable dignity of man, upon the recognition of an indelible and happy equality between men, upon the basic principle of human brotherhood, that is, of the respect and true love due to each man, because he is man'. This same message I affirmed in Mexico and in Poland. I reaffirm it here in Ireland. Every human being has inalienable rights that must be respected. Each human community--ethnic, historical, cultural or religious--has rights which must be respected. Peace is threatened every time one of these rights is violated. The moral law, guardian of human rights, protector of the dignity of man, cannot be set aside by any person or group, or by the State itself, for any cause, not even for security or in the interests of law and order. The law of God stands in judgment over all reasons of State. As long as injustices exist in any of the areas that touch upon the dignity of the human person, be it in the political, social or economic field, be it in the cultural or religious sphere, true peace will not exist. [...] Peace cannot be established by violence, peace can never flourish in a climate of terror, intimidation and death. It is Jesus Himself who said: `All who take the sword will perish by the sword' (Matthew 26:52). This is the word of God, and it commands this generation of violent men to desist from hatred and violence and to repent" ([Pope] John Paul II, "Homily at Drogheda", 29 September 1979).
The peace and joy which Christ brings us should be typical of believers: "Get rid of those scruples that deprive you of peace.--What takes away your peace of soul cannot come from God.
"When God comes to you, you will feel the truth of those greetings: My peace I give to you..., peace I leave you..., peace be with you..., and you will feel it even in the midst of troubles." ([St] J. Escriva, "The Way", 258).
28. Jesus Christ, as Only-begotten Son of God, possesses divine glory for all eternity; but while He is on earth this glory is veiled and hidden behind His holy human nature (cf. 17:5; Philippians 2:7). It only shows itself on a few occasions, such as when He performs miracles (cf. 2:11) or at the Transfiguration (cf. Matthew 17:1-8 and paragraph). Now, through His death, resurrection and ascension into Heaven Jesus will be glorified--in His body also--as He returns to the Father and enters into His glory. Therefore, His departure from this world should be a source of joy for His disciples; but they do not properly understand what He is saying, and they are saddened because they are more aware of the Master being physically separated from them than the glory which awaits Him.
When Jesus says that the Father is greater than He, He is thinking about His human nature; as man Jesus is going to be glorified, ascending as He does to the right hand of the Father. Jesus Christ "is equal to the Father in His dignity, less than the Father in His humanity" ("Athanasian Creed"). St. Augustine exhorts us to "acknowledge the twofold nature of Christ--the divine, by which He is equal to the Father; the human, by which He is less than the Father. But the one and the other are together not two, but one Christ' ("In Ioann. Evang.", 78, 3). However, although the Father and the Son are equal in nature, eternity and dignity, our Lord's words can also be understood by taking "greater" to refer to His origin: only the Father is "beginning without beginning", whereas the Son proceeds eternally from the Father by way of a generation which is also eternal. Jesus Christ is God from God, Light from Light, True God from True God (cf. Nicene Creed).
30. Clearly the world is good, for it has been created by God, and God loved it so much that He sent His Only-begotten Son (cf. John 3:16). However, in this passage "world" means all those who reject Christ; and "the ruler of the world" is the devil (cf. John 1:10; 7:7; 15:18-19). The devil opposed the work of Jesus right from the start of His public life when he tempted Him in the desert (cf. Matthew 4:1-11 and paragraph). Now, in the passion, he will apparently overcome Christ. This is the hour of the power of darkness when, availing of Judas' treachery (cf. Luke 22:53; John 13:27), the devil manages to have our Lord arrested and crucified.
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland.
Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.