This is the message we have heard from him and proclaim to you, that God is light, and in him is no darkness at all. If we say we have fellowship with him while we walk in darkness, we lie and do not practice the truth. But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. If we say we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.

(1 John 1:5-9)

“Penitence is the gateway that leads out of darkness into light. He who does not enter into the light has not properly gone through the gate of repentance; for had he done so, he would have been in the light. He who does not repent commits sin, because he is not penitent, for ‘whoever knows what is right to do and fails to do it, for him it is sin’. He ‘who commits sin is the slave of sin’ and ‘hates the light and does not come to the light, lest his deeds should be exposed’. But now we have willingly and of our own accord entered into the light through penitence…”

– St. Symeon the New Theologian