Truth is the foundation of everything that has been created. Let truth be also the foundation of all your works (both inward and outward), and especially the foundation of your prayers. Let all your life, all your works, all your thoughts, and all your desires be founded upon truth.
No man, wise in his own opinion, because he has studied all the sciences and is learned in external wisdom, will ever penetrate God's mysteries or see them unless he first humbles himself and becomes foolish in his heart, repudiating his self-opinion together with his acquirements of learning. For a man who acts thus and follows with undaunted faith those who are wise in things Divine, is guided by them and with them enters into the city of the living God, and, taught and enlightened by the Holy Spirit, sees and knows things which no one else can see or know. Thus he becomes taught of God.
In the presence of an invisible spirit, the body becomes afraid; but in the presence of an angel, the soul of the humble is filled with joy. Therefore, when we recognize the presence from the effect, let us quickly hasten to prayer, for our good guardian has come to pray with us.
Do not be surprised that you fall every day, do not give up, but stand your ground courageously. And assuredly, the angel who guards you will honor your patience. While a wound is still fresh and warm, it is easy to heal; but old, neglected and festering ones are hard to cure, and require for their care much treatment, cutting, plastering and cauterization. Many from long neglect become incurable, but with God all things are possible.
In the matter of piety, poverty serves us better than wealth, and work better than idleness, especially since wealth becomes an obstacle even for those who do not devote themselves to it. Yet, when we must put aside our wrath, quench our envy, soften our anger, offer our prayers, and show a disposition which is reasonable, mild, kindly, and loving, how could poverty stand in our way? For we accomplish these things not by spending money but by making the correct choice. Almsgiving above all else requires money, but even this shines with a brighter luster when the alms are given from our poverty. The widow who paid in the two mites was poorer than any human, but she outdid them all.
In Christianity truth is not a philosophical concept nor is it a theory, a teaching, or a system, but rather, it is the living theanthropic hypostasis - the historical Jesus Christ (John 14:6). Before Christ men could only conjecture about the Truth since they did not possess it. With Christ as the incarnate divine Logos the eternally complete divine Truth enters into the world. For this reason the Gospel says: 'Truth came by Jesus Christ' (John 1:17).
The angel who is always near us is by nothing so distressed and made indignant as when, without being constrained by some necessity, we deprive ourselves of the ministration of the Holy Mysteries and of reception of Holy Communion, which grants remission of sins. For at that hour the priest offers up the sacrifice of the Body of Him Who gives us life, and the Holy Spirit descends and consecrates the Body and Blood and grants remission to creation. The Cherubim, the Seraphim, and the angels stand with great awe, fear, and joy. They rejoice over the Holy Mysteries while experiencing inexpressible astonishment. The angel who is always by us is consoled, because he also partakes in that dread spectacle and is not deprived of that perfect intercourse.
When you close the doors to your dwelling and are alone you should know that there is present with you the angel whom God has appointed for each man...This angel, who is sleepless and cannot be deceived, is always present with you; he sees all things and is not hindered by darkness. You should know, too, that with him is God, who is in every place; for there is no place and nothing material in which God is not, since He is greater than all things and holds all men in His hand.
He who chooses maltreatment and dishonor for the sake of truth is walking on the apostolic path; he has taken up the cross and is bound in chains (cf. Mt 16:24). But when he tries to concentrate his attention on the heart without accepting these two, his intellect wanders from the path and he falls into the temptations and snares of the devil.
In answer to your question as to what constitutes a happy life, whether splendor, fame and wealth, or a quiet, peaceful, family life, I will say that I agree with the latter, but will add the following: A life lived in humility and with an irreproachable conscience brings peace, tranquility, and true happiness. But wealth, honor, glory and exalted position often serve as the cause of a multitude of sins, and such happiness is not one on which to rely.