The second of four installments of St Symeon the New Theologian's twenty-fourth discourse, "On Spiritual Knowledge" (continued from here):
From the commandments spring the virtues, and from them the revelation of the mysteries that are hidden and veiled in the letter. From the fulfillment of the commandments comes the practice of the virtues; through the practice of the virtues the commandments are fulfilled. Thus by means of these the door of knowledge has been opened to us (cf. Lk 11:52); or, rather, it has been opened, not by them, but by Him who has said, "He who loves Me will keep My commandments, and My Father will love him, and I will reveal Myself to him" (Jn 14:23, 21). When, therefore God "lives in us and moves among us (2 Cor 6:16) and perceptibly reveals Himself to us, then we consciously contemplate the contents of the chest, the divine mysteries that are hidden in the divine Scripture. Le no one deceive himself – in no other way is it possible for the chest of knowledge to be opened to us, and for us to enjoy the good things that it contains and partake of them and contemplate them.Taken from this edition.
But what are these good things of which I speak? They consist in perfect love (that is, toward God and our neighbor), contempt of all things that are visible, mortification of the flesh and "its members that are on the earth" (Col 3:5), including evil desire. Just as a dead man has no thought whatever and perceives nothing, so we ourselves shall have no thoughts of evil desire or of passionate sentiment at any time. We shall not feel the tyrannical oppression of the evil one, but be mindful only of the commandments of our Savior Christ. [We shall think of] immortality, of the incorruption of eternal glory, of the kingdom of heave, of [our] adoption as sons through the regeneration of the Holy Spirit. Thereby we become sons by adoption and grace, we are called "heirs of God and fellow-heirs of Christ" (Rom 8:17), and together with these things we acquire "the mind of Christ" (1 Cor 2:16) and through Him see God and Christ Himself dwelling in us and moving us in a way that we can know (2 Cor 6:16).
All these things are granted to those who hear God's commandments and do them; they enjoy them abundantly together with those unutterable and ineffable things that are above these things, through the opening of the chest of which we have spoken, that is, the uncovering of the eyes of our minds and the contemplation of the things that are hidden in Holy Writ. But others, who lack the knowledge and experience of any of the things of which we have spoken, have no taste of their sweetness, of the immortal life derived from them, since they lean on the mere study of the Scriptures. Nay, rather, this very study will judge and condemn them at their departure [from this life[ even more than those who have not heard the Scriptures at all. Some of these men err through ignorance and pervert all the divine Scriptures (cf. 2 Pet 3:16) as they interpret them in accordance with their passionate desires. They wish to commend themselves (cf. 2 Cor 10:12) as though they were to be saved apart from the exact observance of Christ's commandments, and so they altogether deny the power of Holy Scriptures.