St. John of Kronstadt On The Meaning Of Candles:
The candles burning on the altar represent the non-created Light of the Trinity, for the Lord dwells in an unapproachable light. They also represent the fire of Divinity which destroys ourungodliness and sins. The candles lit before the icons of the Savior signify that He isthe True Light which lighteth every man that cometh into the world (John 1:9); at the same time, He is a Fire which engulfs and revives our souls and bodies. The candles lit before the icons of the Theotokos are a symbol of the fact that She is the Mother of the Unapproachable Light, and also of Her most pure and burning love for God and Her love for mankind. The candles lit before icons of saints reflect their ardent lovefor God for Whose sake they gave up everything that man prizes in life, including their very lives, as did the holy apostles, martyrs and others. These candles also mean that these saints are lamps burning for us and providing light for us by their own saintly living, their virtues and their ardent intercession for us before God through their constant prayers by day and night. The burning candles also stand for our ardent zeal and the sincere sacrifice we make out of reverence and gratitude to them for their solicitude on our behalf before God.
St. Nikolai of Ochrid: Vigil lights are lit for many reasons:
First - because our faith is light. Christ said: "I am the light ofthe world" (John 8:12). The light of the lampada reminds us of that light by which Christ illumines our souls. Second - in order to remind us of the radiant character of thesaint before whose icon we light the lampada, for saints are called sons of light (John 12:36, Luke 16:8). Third - in order to serve as a reproach to us for our dark deeds, for our evil thoughts and desires, and in order to call us to the path of vangelical light; and so that we would more zealously try to fulfill the commandments of the Savior: "Let your light so shine before men, that they may see your good works" (Matthew 5:16). Fourth - so that the lampada would be our small sacrifice to God, Who gave Himself completely as a sacrifice for us, and as a small sign of our great gratitude and radiant love for Him from Whom we ask in prayer for life, and health, and salvation and everything that only boundless heavenly love can bestow. Fifth - so that terror would strike the evil powers who sometimes assault us even at the time of prayer and lead away our thoughts from the Creator. The evil powers love the darkness and tremble at every light, especially at that which belongs to God and to those who please Him. Sixth - so that this light would rouse us to selflessness. Just asthe oil and wick, (or wax), burn in the lampada, submissive to our will, so let our souls also burn with the flame of love in all our sufferings, always being submissive to God's will. Seventh - in order to teach us that just as the lampada cannot be lit without our hand, so too, our heart, our inward lampada, cannot be lit without the holy fire of God's Grace, even if it were to be filled with all the virtues. All these virtues of ours are, after all, like combustible material, but the fire which ignites them proceeds from God. Eighth - in order to remind us that before anything else theCreator of the world created light, and after that everything else in order: "And God said, "Let there be light: and there was light" (Genesis 1:3). And it must be so also at the beginning of our spiritual life, so that before anything else the light of Christ's truth would shine within us. From this light of Christ's truth subsequently every good is created, springs up and grows in us.