We make mention [in the Divine Liturgy] also of the Seraphim, whom Isaiah in the Holy Spirit saw standing around the throne of God, and with two of their wings veiling their face, and with two their feet, while with two they did fly, crying 'Holy, Holy, Holy, is the Lord of Hosts' (Isaiah 6:2-3). For the reason of our reciting this confession of God, delivered down to us from the Seraphim, is this, that so we may be partakers with the hosts of the world above in their hymn of praise.
Without temptations, pure souls are not known, virtue does not show, patience is not discernible. Without temptations, it is impossible for the soul to become healthy. They are the cleansing fire which makes the soul pure and bright.
He therefore, the God Who rules over all things, must stretch out a saving hand to the wandering sheep, whom the Supreme Shepherd has now in fact redeemed. For He looked for it as it wandered afar, and He has placed it in a secure sheepfold, safe against thieves and wild beasts: namely, His Church.
Watch constantly, learning to understand God's law, for this warms the heart with heavenly fire. Guard your lips from the idle word, or empty talk, lest the heart gets used to evil words.
The grace of repentance, which acts in those who struggle, is a patristic inheritance. It is a divine transaction and exchange in which we give dust and receive heaven. We exchange matter for the Spirit. Every drop of sweat, every pain, every ascesis for God is an exchange.
To act 'according to one’s strength' means to use a little less than necessary both of food, and drink, and sleep... As for food, restrain yourself when you wish to eat a little more, and in this way you will always make use of it moderately.
Leave off all evasions, bend your neck to humility and obedience, and you will receive mercy. If you practice with humility and obedience what you hear from the fathers, God will grant you His blessed help not only in the work you are doing, but will make all your works successful, for He protects the path of those who fear Him and watches their progress.
Have great concern for these portals the eyes. Most robbers enter through these portals to overthrow the castle of the soul. Had the forefathers guarded their eyes, they would not have been exiled far from God and Paradise. 'The woman saw that the fruit of the tree was good...' (Gn 3:6).