Why do we light a lamp?
Light symbolises knowledge; and darkness, symbolises ignorance. The Lord is the ‘Knowledge Principle’ (caitanya) who is the source, the enlivener and the illuminator of all knowledge. Hence light is worshipped as the Lord Himself.
Knowledge removes ignorance just as light removes darkness. Also knowledge is a lasting inner wealth by which all outer achievements can be accomplished.
Hence we light the lamp to bow down to knowledge as the greatest of all forms of wealth. Knowledge backs all our actions, whether good or bad. We, therefore, keep a lamp lit during all auspicious occasions as a witness to our thoughts and actions.
Why not light a bulb or tube light? That too would remove darkness. But the traditional oil lamp has a further spiritual significance. The oil or ghee in the lamp symbolises our vasanas or negative tendencies and the wick, the ego.
When lit by spiritual knowledge, the vasanas get slowly exhausted and the ego too finally perishes. The flame of a lamp always burns upwards. Similarly, we should acquire knowledge which takes us towards higher ideals.
A single lamp can light hundreds more, just as a man of knowledge can give it to many more. The brilliance of the light does not diminish despite its repeated use to light many more lamps.
So too, knowledge does not lessen when shared with or imparted to others. On the contrary it increases in clarity and conviction, when shared. It benefits both the receiver and the giver.