Only the gospel of Christ fully knows the mystery of sin and the problem of sin and everything which hides within it. The prodigal son of the Gospel is the perfect example of the repentant sinner. The Gospel shows us that man, through his free will, can share his life with Earth and with Heaven, with Satan and with God, with paradise and with hell. Sin gradually strips man of everything divine in him, paralyzes his every divine inclination and desire, until it finally throws him into the bosom of Satan. And then man reaches the plight of grazing the swine of his master, the Devil. The swine are passions, which are always greedy and gluttonous. In such a life, the unfortunate man is nothing more than insane. In a shocking parable of the Gospel, the Lord says about the prodigal son, ‘he came to himself,’ (Luke 15:17) How did he come to himself? He came to himself through repentance. Through sin, man becomes mad, insane. Every sin, even the most seemingly insignificant one, is always an insanity of the soul. Through repentance, man comes to his senses becomes complete again, comes to himself. Then he cries out loud to God, runs to Him, and cries towards Heaven, ‘Father, I have sinned against Heaven, and in thy sight’ (Luke 15:21). And what is the heavenly Father doing? He is always infinitely merciful upon seeing His child in a state of repentance. He has compassion for him, runs, embraces him, and kisses him. He orders His heavenly hosts, the holy angels: ‘Bring forth the best robe and put it on him; and put a ring on his hand, and shoes on his feet: and bring hither the fatted calf, and kill it; and let us eat, and be merry: for this is My son who was dead, and is alive again; and he was lost, and is found. And they began to be merry.’ (Luke 16:22-24) And this is taking place for each and every one of us, and for the sake of every sinner who repents. Namely, joy and happiness is taking place in the heaven of the All-merciful Lord and God, and together with Him, all of the holy angels.

St. Justin Martyr

The aim of all those who live in God is to please our Lord Jesus Christ and become reconciled with God the Father through receiving the Holy Spirit, thus securing their salvation, for in this consists the salvation of every soul. If this aim and this activity is lacking, all other labour is useless and all other striving is in vain. Every path of life which does not lead to this is without profit.

St. Symeon the New Theologian

If we love our enemies, there will be no place in our souls for pride, for in Christ-like love no one ranks above another.

St. Silouan the Athonite

What is necessary to have peace in soul and body? We must love all men as ourself, and be ready for death at all times.

St. Silouan the Athonite

Take, in the next place, the subjection by which you subject the Son to the Father. What, you say, is He not now subject, or must He, if He is God, be subject to God? You are fashioning your argument as if it concerned some robber, or some hostile deity. But look at it in this manner: that as for my sake He was called a curse, who destroyed my curse; and sin, who takes away the sin of the world; and became a new Adam to take the place of the old, just so He makes my disobedience His own as Head of the whole body. 

As long then as I am disobedient and rebellious, both by denial of God and by my passions, so long Christ also is called disobedient on my account. But when all things shall be subdued unto Him on the one hand by acknowledgment of Him, and on the other by a reformation, then He Himself also will have fulfilled His submission, bringing me whom He has saved to God. For this, according to my view, is the subjection of Christ; namely, the fulfilling of the Father’s Will. But as the Son subjects all to the Father, so does the Father to the Son; the One by His Work, the Other by His good pleasure, as we have already said. And thus He Who subjects presents to God that which he has subjected, making our condition His own. Of the same kind, it appears to me, is the expression, ‘My God, My God, why hast Thou forsaken Me?’ It was not He who was forsaken either by the Father, or by His own Godhead, as some have thought, as if It were afraid of the Passion, and therefore withdrew Itself from Him in His Sufferings (for who compelled Him either to be born on earth at all, or to be lifted up on the Cross?) But as I said, He was in His own Person representing us. For we were the forsaken and despised before, but now by the Sufferings of Him Who could not suffer, we were taken up and saved. Similarly, He makes His own our folly and our transgressions; and says what follows in the Psalm, for it is very evident that the 22nd Psalm refers to Christ.

St. Gregory the Theologian

As a fish cannot swim without water, and as a bird cannot fly without air, so a Christian cannot advance a single step without Christ.

St. Gregory the Theologian

But nothing causes such exceeding grief as when anyone, lying under the captivity of sin, calls to mind from where he has fallen, because he turned aside to carnal and earthly things, instead of directing his mind in the beautiful ways of the knowledge of God. So you find Adam concealing himself, when he knew that God was present and wishing to be hidden when called by God with that voice which wounded the soul of him yourself? Why are you concealed? Why do you avoid Him Whom you once longed to see? A guilty conscience is so burdensome that it punishes itself without a judge, and wishes for covering, and yet is bare before God.

St. Ambrose of Milan

In order that you may move your will more easily to this one desire, in everything—to please God and to work for His glory alone—remind yourself often that He has granted you many favors in the past and has shown you His love. He has created you out of nothing in His own likeness and image, and has made all other creatures your servants; He has delivered you from your slavery to the devil, sending down, not one of the angels, but His Only-begotten Son to redeem you, not at the price of corruptible gold and silver, but by His priceless blood and His most painful and degrading death. Having done all this He protects you, every hour and every moment, from your enemies; He fights your battles by His divine grace; in His immaculate Mysteries He prepares the Body and Blood of His beloved Son for your food and protection. All this is a sign of God’s great favor and love for you; a favor so great that it is inconceivable how the great Lord of hosts could grant such favors to our nothingness and worthlessness.

St. Nicodemus of life Holy Mountain

One should not seek among others the truth that can be easily gotten from the Church. For in her, as in a rich treasury, the apostles have placed all that pertains to truth, so that everyone can drink this beverage of life. She is the door of life.

St. Irenaeus of Lyon

If you find that there is no love in you, but you want to have it, then do deeds of love, even though you do them without love in the beginning. The Lord will see you desire and striving and will put love in your heart.

St. Ambrose of Optina

Christ prayed for those that crucified Him: ‘Father, count not this sin against them; they know not what they do.’ Archdeacon Stephen prayed for those who stoned him so that the Lord would not judge this sin against them. And so we, if we wish to retain grace, must pray for our enemies. If you do not find pity on a sinner who will suffer in flames, then you do not carry the grace of the Holy Spirit, but rather an evil spirit; and while you yet live, you must free yourself from his clutches through repentance.

St. Silouan the Athonite

 I ask you to try something. If someone grieves you, or dishonors you, or takes something of yours, then pray like this: “Lord, we are all your creatures. Pity your servants, and turn them to repentance,” and then you will perceptibly bear grace in your soul. Induce your heart to love your enemies, and the Lord, seeing your good will, shall help you in all things, and will Himself show you experience. But whoever thinks evil of his enemies does not have love for God and has not known God.

St. Silouan the Athonite

They tell the story that on one occasion, while the blessed Anthony [St. Anthony the Great] was dwelling in the desert, thoughts of dejection and despair rose up in his mind, and he was in deep gloom of thought, and said to God, "Lord, I wish to live, but my thoughts will not permit me to do so. What will I do in my tribulations to be saved?" And he came a little nearer [to the town] from the place where he was, and he saw a man who was like to himself, and was in his own form, and he was sitting down and twisting palm leaves into ropes ; and this man rose up from his work, and prayed, and afterwards he sat down again and continued his work, and then he stood up once more, and prayed. Now the man was an angel who had been sent from God to correct and to admonish the blessed Anthony, who afterwards heard him say to him, "O Anthony, do you also do this and live"; and when Anthony heard this, the blessed man had great joy, and afterwards he did as the angel had done, and lived.

from Sayings of the Holy Desert Fathers

Such are the souls of the saints: they love their enemies more than themselves, and in this age and in the age to come they put their neighbor first in all things, even though because of his ill-will he may be their enemy. They do not seek recompense from those whom they love, but because they have themselves received they rejoice in giving to others all that they have, so that they may conform to their Benefactor and imitate His compassion to the best of their ability; "for He is bountiful to the thankless and to sinners" (cf. Luke 6:35).

St. Peter of Damascus

“I have not come,” says the Lord, “to bring peace on earth (that is, love of parents for sons, and love of brothers for brothers who have resolved to serve Me), but war and a sword” in order to separate lovers of God from lovers of the world, the lovers of material things from lovers of spiritual things, the lovers of fame from the humble-minded.

St. John Climacus

In the words of the psalmist, "As you lie in bed, repent of what you say in your heart" (Ps. 4:4 LXX), that is, repent in the stillness of the night, remembering the lapses that occurred in the confusion of the day and disciplining yourself in hymns and spiritual songs (cf. Col. 3:16) – in other words, teaching yourself to persist in prayer and psalmody through attentive meditation on what you read. For the practice of the moral virtues is effectuated by meditating on what has happened during the day, so that during the stillness of the night we can become aware of the sins we have committed and can grieve over them.

St. Peter of Damascus

Repentance must be the soul of prayer, without which prayer is dead, stinking with proud and seductive conceit!  Repentance is the only door through which one can obtain from our Lord the saving pasture.  He who neglects repentance is bereft of all grace...  The merciful Lord prepared the way for our divine heavenly eternal Kingdom, showed the door through which we might enter into the salvic pasture of the Holy Spirit and Truth, the door of repentance.  If we neglect to repent, without any doubt, we will remain outside the door.  Good deeds, natural in feeling, will in no way replace repentance.

St. Ignatius Brianchaninov

What does it mean to take up your cross? It means the willing acceptance, at the hand of Providence, of every means of healing, bitter though it may be, that is offered. Do great catastrophies fall on you? Be obedient to God’s will, as Noah was. Is sacrifice demanded of you? Give yourself into God’s hands with the same faith as Abram had when he went to sacrifice his son. Is your property ruined? Do your children die suddenly? Suffer it all with patience, cleaving to God in your heart, as Job did. Do your friends forsake you, and you find yourself surrounded by enemies? Bear it all without grumbling, and with faith that God’s help is at hand, as the apostles did.

St. Nikolai Velimirovich

The Lord said: Verily I say unto you, Inasmuch as ye have done it unto one of the least of these My brethren, ye have done it unto Me (Matthew 25:40). 

Similar things happen in almsgiving and in Holy Communion. In Holy Communion we receive the Living Lord Christ Himself, in the form of bread and wine; in almsgiving we give to the Living Lord Christ Himself, in the form of the poor and needy. A certain man in Constantinople was unusually merciful. Walking along the streets of the city, he would press his gift into the hands of the poor and hurry onward, so he would not hear their gratitude or be recognized. When a friend of his asked how he had become so merciful, he replied: “Once in church I heard a priest say that whoever gives to the poor, gives into the hands of Christ Himself. I didn’t believe it, for I thought, ‘How can this be, when Christ is in heaven?’ However, I was on my way home one day and I saw a poor man begging, and the face of Christ shone above his head! Just then a passerby gave the beggar a piece of bread, and I saw the Lord extend His hand, take the bread, and bless the donor. From then on, I have always seen Christ’s face shining above the beggars. Therefore, with great fear I perform as much charity as I can."

St. Nikolai Velimirovich

Brethren and fathers, God, who fashioned us and brought us out of non-existence into being, has placed us in this life as in a schoolroom to learn to gospel of his kingdom.

St. Theodore the Studite