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 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 our ungodliness and sins. The candles lit before the icons of the Savior signify that He is the 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.
If the words of God are uttered merely as verbal expressions, and their message is not rooted in the virtuous way of life of those who utter them, they will not be heard. But if they are uttered through the practice of the commandments, their sound has such power that they dissolve the demons and dispose men eagerly to build their hearts into temples of God through making progress in works of righteousness.
Just as the human word which proceeds naturally from the mind is messenger of the secret movements of the mind, so does the Word of God, who knows the father by essence as Word knows the Mind which has begotten it (since no created being can approach the Father without Him), reveal the Father whom He knows. As the Word of God by nature, He is spoken of as the 'messenger of the great plan of God'.
The candles lit before icons of saints reflect their ardent love for 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.
