They (namely the Apostles) have not handed down everything in writing, but have also delivered many things in unwritten form. The former and the latter are equally trustworthy, and so we also consider the [unwritten] Tradition of the Church to be trustworthy. Is it Tradition? Seek no further.
Two factors are involved in man's salvation: the grace of God and the will of man. Both must work together, if salvation is to be attained. Repentance is a Mysterion through which he who repents for his sins confesses before a Spiritual Father who has been appointed by the Church and has received the authority to forgive sins, and receives from this Spiritual Father the remission of his sins and is reconciled with the Deity, against Whom he sinned. Repentance signifies regret, change of mind. The distinguishing marks of repentance are contrition, tears, aversion towards sin, and love of the good.
Let us have recourse to humility on all occasions; for the humble lie prone on the ground, and how can a man fall if he lies on the ground? But a man who stands on a height can easily fall.
What does it mean to be as wise as a serpent? When a serpent is attacked, it is willing to have much of its body severed, as long as it saves the head. So to be wise as a serpent means to be willing to lose everything - your wealth, your reputation, your friends - as long as you save your faith. Your faith is your head, by which you learn all truth; and by that truth your soul is set free. We should, however, recognize that the wisdom of the serpent is not enough; we must be honest and innocent as doves. Indeed it is the combination of wisdom and innocence that creates virtue. The person who is wise as a serpent can sustain the most terrible attacks and still continue to flourish as a disciple of Christ. The person who is innocent refuses to retaliate against those who make the attacks. To be as innocent as a dove means never to take revenge on those who wrong you or undermine you. Unless wisdom is tempered by innocence, one attack provokes another, and conflict continues without end. Unless innocence is tempered by wisdom, a person is so vulnerable that he will not even survive a single attack. Rest assured that no one can ever take away your faith; your wisdom guards against that. But be careful never to bear a grudge against anyone who does you wrong.
We cannot be saved by seeking just our own individual salvation; we need to look first to the good of others. In warfare, the soldier who takes to flight to save his own skin brings disaster on himself as well as on the others, whereas the good soldier who takes up arms on behalf of his comrades saves his own life along with theirs.
Those who mourn and those who are insensitive are not subject to fear, but the cowardly often have become deranged. And this is natural. For the Lord rightly forsakes the proud that the rest of us may learn not to be puffed up.
For the Antichrist will come for the destruction of men, and to injure them, for what will he not then work? He will change and confound all things, both by his commandments and by the fear of him. He will be terrible in every way: by his power and by his unlawful commandments.’
Concerning fasting, do not grieve, as I have said to you before: God does not demand of anyone labors beyond his strength. And indeed, what is fasting if not a punishment of the body in order to humble a healthy body and make it infirm for passions, according to the word of the Apostle: 'When I am weak, then am I strong' (II Corinthians 12:10).
Until we have acquired true prayer, we are like those who introduce children to walking. Make the effort to raise up, or rather, to enclose your mind within the words of your prayer; and if, like a child, it gets tired and falters, raise it up again. The mind, after all, is naturally unstable, but the God Who can do everything can also give it firm endurance. Persevere in this, therefore, and do not grow weary...
The body is a slave, the soul a sovereign, and therefore it is due to Divine mercy when the body is worn out by illness: for thereby the passions are weakened, and a man comes to himself; indeed, bodily illness itself is sometimes caused by the passions.