The kingdom of God is within us when God reigns in us, when the soul in its depths confesses God as its master, and is obedient to Him in all its powers. Then God acts within it as master ‘both to will and to do of his good pleasure’ (Phil. ii. 13). This reign begins as soon as we resolve to serve God in our Lord Jesus Christ, by the grace of the Holy Spirit. Then the Christian hands over to God his consciousness and freedom, which comprises the essential substance of our human life, and God accepts the sacrifice; and in this way the alliance of man with God and God with man is achieved, and the covenant with God, which was severed by the fall and continues to be severed by our willful sins, is re-established. This inner alliance is sealed, confirmed, and given the strength to maintain itself by the power of grace in the divine sacrament of baptism, and for those who have fallen after baptism, in the sacrament of repentance: and afterwards it is constantly strengthened by holy communion. All Christians live thus; and consequently they all bear the kingdom of God within themselves, that is to say they obey God as King and are ruled by God as King.
You ask, 'Must one do something?' Of course one must! And do whatever comes along-in your circle of friends and in your surroundings-and believe that this is and will be your real work. More will not be demanded of you. It is a great misconception to think, whether for the sake of heaven or, as the modernists put it, to 'make one's mark on humanity,' that one must undertake great, reverberating tasks. Not at all. It is necessary only to do everything according to the commandments of God. Just what exactly? Nothing in particular - only those things which present themselves to everyone in the circumstances of life, those things which are required by the everyday happenings we all encounter. Let's take an example: a beggar comes up to you; it is God Who has brought him. God has brought you the beggar, of course, desiring you to act toward this beggar in a manner pleasing to Him, and He watches to see what you will actually do. It will please Him if you help. Will you? If you do what is pleasing to God, you will be taking a step toward the ultimate goal, the inheritance of heaven. Generalize this occurrence, and you will find that in every situation and at every encounter one must do what God wants him to do. And we know truly what He wants from the commandments He has given us. If someone seeks help, then help him. If someone has offended you, forgive him. If you yourself have offended someone, then hasten to ask forgiveness and to make peace. If someone has praised you, do not be proud. If someone has scolded you, do not get angry. If the time has come to pray, then pray. To work, then work, - etc. etc.
Set your sight on heaven and order every step of your life so that it will be a step in that direction. It seems to me that it is all so simple, and yet so all-embracing.
St. John Climacus was asked if there are reliable signs by which it's possible to know whether a soul is drawing near to God or moving away from Him. After all, regarding ordinary things there are clear signs as to whether they're good or not. When, for instance, cabbage, meat or fish begins to rot, it's easy to notice it, since the rotting object begins to give off a foul odor, the color and taste change, and its external appearance witnesses to its deterioration. Well, and what about the soul? After all, it's bodiless and can't give off a bad smell or change its appearance. To this question the Holy Father replies, 'A sure sign of the deadening of the soul is the avoidance of church services.'
This reversal of thoughts is the strongest means, not only for repelling accidental critical thoughts, but also for completely freeing yourself of this vice…
Keep your mind from malicious thoughts of your neighbors, knowing that such thoughts are hurled by diabolical power, to keep your mind from your own sins and from seeking.
You have the book of discourses by St. Macarius of Egypt. Kindly read the 19th discourse, concerning a Christian's duty to force himself to do good. There it is written, 'One must force oneself to pray, even if one has no spiritual prayer.' And, 'In such a case, God, seeing that a man earnestly is striving, pushing himself against the will of his heart (that is, his thoughts), He grants him true prayer.' By true prayer, St. Macarius means the undistracted, collected, deep prayer that occurs when the mind stands unswervingly before God. As the mind begins to stand firmly before God, it discovers such sweetness, that it wishes to remain in true prayer forever, desiring nothing more.
The simplest means for confining the will within its proper bounds lies in disposing children to do nothing without permission. Let them be eager to run to their parents and ask: May I do this or that? They should be persuaded by their own experience and that of others that to fulfill their own desires without asking is dangerous; they should be put in such a frame of mind that they even fear their own will.
Patient endurance kills the despair that kills the soul; it teaches the soul to take comfort and not to grow listless in the face of its many battles and afflictions.
If the main goal of the repentant sinner should be total, light-bearing and blessed communion with God, then the main hindrance to this is the existence of the passions still active and working in him - the virtues being as yet unsealed in him - and the unrighteousness of his powers. Therefore his main work upon conversion and repentance should be the uprooting of the passions and sealing the virtues - in a word, correcting himself.
The first duty of a Christian, of a disciple and follower of Jesus Christ, is to deny oneself. To deny oneself means to give up one's bad habits, to root out of the heart all that ties us to the world; not to cherish bad desires and thoughts; to quench and suppress bad thoughts; to avoid occasions of sin; not to do or desire anything from self-love but to do everything out of love for God. To deny oneself means, according to the Apostle Paul, to be dead to sin and the world, but alive to God.
As it is not possible to walk without feet or fly without wings, so it is impossible to attain the Kingdom of Heaven without the fulfillment of the commandments.
Even if a person’s sin is not only obvious, but very grievous and comes from a hardened and unrepentant heart, do not condemn him, but raise your eyes to the wondrous and incomprehensible judgments of God; then you will see that many people, formerly full of iniquity, later repented and reached a high degree of sanctity, and that, on the other hand, others, who were on a high level of perfection, fell into a deep abyss. Take care, lest you also suffer this calamity through judging others.
Then we say: 'Forgive us our trespasses as we forgive those who trespass against us.' Brothers, praying thus, we should very much fear lest the Lord reply to these words of our prayer: 'The judgments you give are the judgments you will get, and the amount you measure out is the amount you will be given.' And you who ask this, see whether you did to no one what you did not want done to you. Therefore before we hear these words of the Lord, brethren, let us first examine our hearts as to whether we are with justice asking of the Lord what we have not denied to those asking us. We ask that our trespasses be forgiven us. God hears and He wants to forgive us, but only if we first pardon those who ask us to do likewise.
If we desire to acquire faith the foundation of all blessings, the door to God's mysteries, unflagging defeat of our enemies, the most necessary of all the virtues, the wings of prayer and the dwelling of God within the soul--we must endure every trial imposed by our enemies and by our many and various thoughts... if we forcibly triumph over the trials and temptations that befall us, it will not be we who are victorious, but Christ, Who is present in us through faith.