The Gospel calls upon man to believe in the truth of Christ's teaching, calls upon him to follow the teaching and life of the Savior of the world as the true criterion of goodness, the ideal of spiritual perfection. The Gospel invites all those who thirst for salvation to know the truth in Christ, and the Lord gives them His grace to help them for this. Faith, therefore, in the initial stage of its development, is the knowledge of the truth in Christ; "God and Christ, the Son of God, is revealed and known" in the word of God given to people. From the true knowledge of God, a living faith is kindled in the soul of man, without which it is impossible to be saved (3:205).

From the above-quoted statement of the saint we can conclude that the word "knowledge" must be understood as the very perception by the mind of things that are not subject to direct human observation, the rational acceptance of the Gospel truths on the basis of the testimonies of the word of God. This "knowledge" is the beginning of true faith, so that faith necessarily presupposes knowledge, and knowledge passes into faith. "True faith and true knowledge of God are inseparable, that is, where there is true knowledge of God, there is also true faith; and where there is true faith, there is also true knowledge of God" (3:76). Faith must necessarily be combined with rational knowledge of its object, but such a combination of faith and knowledge is possible only up to certain limits, which are determined by the capabilities of human reason. Descending from heaven as a gift of divine grace, faith communicates truths so high that the limited mind of man is unable to comprehend them. At this stage of comprehension of the Divine Mysteries, faith subordinates reason, for "faith... where our mind does not comprehend" (3:11). It is impossible to comprehend with the mind, for example, such dogmatic truths as the transubstantiation in the Holy Eucharist by the grace of the Holy Spirit of bread into the Body and wine into the Blood of Christ, the act of the universal resurrection of the dead, the presence in eternity of the grace-filled life of the righteous and the torments of condemned sinners, and others. All of them do not belong to the realm of reason, but to living, active faith, which is based on the truths of the word of God (3:11). "Without faith," says St. Tikhon, "we can neither understand nor speak of things to come and things invisible" (5:49). Such faith, in its essence and origin, is a divine gift to fallen man, which he must carefully preserve and develop.

However, knowledge of Christian doctrine and faith in the truth of Divine dogmas cannot in themselves grant salvation to a person. "By faith alone the knowledge of the Holy Mysteries and the dogmas of the Orthodox," writes the saint, "does not lead to salvation" (3:11). It is not enough to know about God and His providential actions in the world. He who believes must accept the gospel of Christ with all the strength of his soul, the truths of faith must be imprinted not only in his mind, but also in his heart, because "faith... the saint has her place not in outward appearance, but in the heart" (3:24). Such faith spiritualizes all the movements of the heart of a person, prompts him to personal participation in the matter of assimilating the fruits of Christ's saving sacrifice. Penetrating through heartfelt faith into the meaning of the salvific Divine Mysteries, the Christian begins to understand more deeply and realize the boundlessness of the Podvig of the Son of God, which He undertook for the salvation of fallen man, as well as His love and blessings, which are poured out to this day upon all mankind (5:12). That is why heartfelt conviction and assurance are the foundation of true and living faith, which draws man into the mysterious spheres of heavenly life. Therefore, in order for the truths of faith to be effective and perceptible to the mind, they must first of all find a response in the soul of a person, be imprinted in his heart, and evoke a desire to live in Christ and with Christ. Only in this case will a Christian be able to properly steer the ship of his soul to the quiet haven of salvation.

Without a living faith in God, which is able to renew the spirit of man and encourage him to wage a struggle against sin, a Christian becomes an old man and is no longer capable of a God-pleasing life (3:181). Faith is the foundation of man's activity, the beginning and motive force of his spiritual life. St. Tikhon compares faith to the root of a plant: just as a small plant, strengthened by its root, begins to rise above the ground and finally turns into a large tree that bears abundant fruit, so a Christian who has faith in his soul is able to grow spiritually, to subdue the flesh to the spirit, and to ascend from strength to strength along the path that leads to eternal life (3:28).

As the driving force of the moral growth of a Christian, faith is unfailingly manifested in all his external actions and deeds, and especially in good deeds, which the saint calls the fruits of living faith (3:237). By its outward expression, true faith embraces, as it were, the entire personality of man, the entire essence of his inner life and external behavior.

The perfection of faith has the closest connection with the inner, spiritual progress of the Christian. Perfect faith moves the whole being of man to strive to live according to the principles of the Divine commandments, directs all his strength to Christ and complete obedience to His all-holy will. Therefore, the spiritual perfection of a Christian, his salvation is inconceivable without perfect faith. In the words of St. Tikhon, "the more faith in a person deepens and multiplies, the more a person grows spiritually, ascends, and the more spiritual fruits grow" (1:68). And in another place he says: "The more faith grows, the more the faithful succeed. As the tree has branches, leaves, and fruit, so does the faithful man have works, words, and thoughts" (3:28). Good works, therefore, are not important in themselves, they cannot be an end in themselves, but must have an indissoluble and living connection with faith, be spiritualized by its influence. According to the laws of spiritual life, good works reveal and strengthen faith, making it more and more effective and perfect (3:28-29).

Such perfect faith unites the soul of the faithful with Christ, as the bride with the bridegroom (3:19); it attracts to him the grace-filled gifts of the Holy Spirit (5:286), creates joy and consolation in the heart (1:108). Directing the whole being of man to God, to eternal and eternal life, grace-filled faith reveals to the Christian the depth of the truths of Divine Revelation, for it "understands everything in the holy word of God of the revelation of the mystery" (1:155).

Faith, on the other hand, teaches a Christian to preserve piety and to be virtuous in any conditions of life. There are no circumstances in life in which the beneficial influence of faith is not manifested. In wealth it makes a man charitable, in the pleasures of life — temperate, in the midst of honors it protects from pride. Faith comforts in sorrows, helps in sickness, and gives patience in suffering (3:18; 1:71). Faith, finally, "turns away from the sins and vanity of the world" (4:375), gives strength and strength to fight against Satan and his servants (3:443). It "receives this strength and strength from Christ the Son of God, on Whom, as on a firm and unshakable foundation, it rests" (3:443).

True faith, assimilated by the mind and heart, perceived by the whole being of man, is the all-embracing guiding principle of the life of a Christian, penetrating all his forces and abilities. At this stage of its development, faith exerts a decisive influence on the will of man. This influence is manifested in the act of conscious and free striving of the believer on the path to eternity. A Christian becomes independent of everything sinful, alien and hostile to his truly God-like being. It "frees the believer from sin, death, oath, hell, the devil, and other calamities, and makes him spiritually free... For no one can enslave, captivate, bind, imprison, kill, "... where the Spirit of the Lord is, that is freedom" (2 Corinthians 3:17)" (3:17).

Having pointed out in his writings the significance of the true faith, the Holy Father defines its essence as follows: "Take note to whom does God give His help and whom does He save? Who are right in their hearts. Who is right in heart? Answer: Those who have sincerely converted, and believe in Him, and go to the news of life, will follow His wills and please Him with all their hearts, — by this God gives His help, and these He saves" (1:205). In other words, only living and active faith, which brings worthy fruits of Christian piety and obedience to the Divine commandments, is pleasing to God. Such faith is the foundation of the true, God-like life of the Christian, which is the harbinger of his future glorified state in the Kingdom of the Heavenly Father.

Having defined the essence of saving faith and its significance in the spiritual life of man, the divinely wise saint, moved by pastoral concern for the salvation of people, did not ignore the negative side of the question under consideration.

In one of his exhortations, he writes that faith, "which is only on the lips and not in the heart" (2:89), is "false and charming" and therefore cannot save man (2:73). And those who confess the name of God, attend the temple of God, but do not live according to the faith, cannot be called Christians (3:100).

A person in whom there is no true and living faith is like one who walks in darkness. Such people do not "distinguish one thing from another; they do not separate good from evil, they do not distinguish between benefit and harm, they fall from sin into sin" (4:9). Just as the fruits of a living and active faith are Christian virtues, so the fruits of its impoverishment are vicious inclinations and works (2:57). Revealing the reasons for the impoverishment of faith, the saint points out that this spiritual ailment originates in the mind and heart of a person. The measure of the impoverishment of faith, as a rule, determines the degree of the Christian's sinful fall. "When faith in a person is completely impoverished," writes the Holy Father, "a person will completely deteriorate... Its fruits are such as it is inside: its mind is filled with unlike, vain, and filthy thoughts" (1:69). After the complete impoverishment of faith, the Christian becomes incapable of walking the path of salvation; deviating towards evil, he completely dies spiritually and begins to serve not God, but the devil. In such a state, a person's mind is constantly filled with filthy and impure thoughts and desires. "From the heart proceed all lusts and lusts, pleasing to the corrupt nature... And so all his mouths are instruments for iniquity, all such will become sin: iniquity thinks, iniquity speaks, iniquity doeth" (1:69).

As St. Tikhon shows, the impoverishment of faith comes from inner coldness and indifference, negligence and unwillingness to kindle the gift of faith. And where there is no living faith, there is no Christ, consequently there is no salvation (1:108). That is why "you must take faith more than your life; and we must lay down our lives for the faith" (1:108). For this, all those seeking salvation must preserve and strengthen in their souls a living and active faith in Christ and not fulfill the sinful lusts of the flesh, not cling with their hearts to worldly things, glory, riches and the honors of temporal life. And if external sinful passions contribute to the cooling of faith in God in the soul of a Christian, then all the more should one beware of even more pernicious internal habits, i.e. impure lust, "anger, malice, envy, hatred, pride, and others" (3:192). All these passions destroy the union of man with God, finally destroy faith and, finally, remove him from the Source of life – God.