Supreme Shakti (power) is the form of God. Shakti is described in three forms:
1. Gyān shakti (power of knowledge),
2. Dravya shakti (power of wealth) and
3. Kriyā shakti (power of performing deeds)
This is why we worship Shakti in three forms – Maa Saraswati (power of knowledge), Maa Lakshmi (power of wealth) and Mahakali (power of performing deeds).
Any activity that takes place is through these three powers. For example, to make a garland of flowers, we need various coloured and variety of flowers. This is the power of wealth. Making the garland is the power of doing this activity and knowledge on how to make it is the power of knowledge. The garland will only be complete if these three powers get together.
Similarly, when one prepares food in the house, one requires spices, vegetable, flour and all sorts of ingredients. This is the power of wealth. The knowledge on how to make the curry or bread is the power of knowledge and to actually cook is the power of performing this activity or deed. Life can only continue with these three powers.
The worship of these three powers is Navratri. The first three days are for the worship of Mahakali (power of performing activities), the next three days are dedicated to Maa Lakshmi (power of wealth) and during the last three days we worship Maa Saraswati who is the power of knowledge.