LITURGY II PETER 1
10 Therefore, brethren, be even more diligent to make your calling and election sure, for if you do these things you will never stumble; 11 for so an entrance will be supplied to you abundantly into the everlasting kingdom of our Lord and Savior Jesus Christ. 12 Therefore I will not be negligent to remind you always of these things, though you know them, and are established in the present truth. 13 Yes, I think it is right, as long as I am in this tent, to stir you up by reminding you, 14 knowing that shortly I must put off my tent, just as our Lord Jesus Christ showed me. 15 Moreover I will be careful to ensure that you always have a reminder of these things after my decease. 16 For we did not follow cunningly devised fables when we made known to you the power and coming of our Lord Jesus Christ, but were eyewitnesses of His majesty. 17 For He received from God the Father honor and glory when such a voice came to Him from the Excellent Glory: "This is My beloved Son, in whom I am well pleased." 18 And we heard this voice which came from heaven when we were with Him on the holy mountain. 19 We also have the prophetic word made more sure, which you do well to heed as a light that shines in a dark place, until the day dawns and the morning star rises in your hearts;
Remember constantly that the light of your soul, of your thoughts, and of your heart comes from Jesus Christ. He is the 'light of the eye' of your heart - not like the light that comes-from the sun, that appears and disappears, and does not penetrate through an opaque substance, but leaves many things in darkness, and cannot enlighten one single soul in the darkness of sin, but He is the 'true light, which enlightens every man (that is the principal part of his being, the soul) that comes into the world' (John 1:9). Yes, the light of Christ enlightens all, even the heathens. 'A light to lighten the Gentiles' (Luke 2:32). It shines even in the darkness of sin, but sinful human darkness, or rather, the men living in the darkness of sin, do not understand It, 'comprehend It not' (John 1:5); they do not guess that the light which is in their souls is from Christ and think that it is their own natural light, that they themselves, by means of their natural intellect, their own sagacity and judgment, have attained to a certain truth, have accomplished certain work; they do not think that it is only by the light of Christ that they see every light (Ps. 36:9), the light of every noble science, of every noble art, and of every thing.
St. John of Kronstadt. My Life in Christ. B# 61.