Every Hindu festival has a spiritual message. This nine-day festival celebrates the triumph of good over evil. In fact the theme of the entire Vedas is reflected in the Navaratri festival: first remove all negativities; then purify the mind and cultivate positive virtues; and finally gain spiritual knowledge and transcend all limitations.Nava means nine and ratri means night. During these nine nights the Mother Goddess is worshipped in her variously manifested forms as Durga, Laxmi and Saraswati.
On the first three nights Durga is invoked for her strength and ferocity which are required to cut out from the mind it’s strong rooted, deep-seated negative tendencies. Goddess Laxmi is (then) worshipped on the next three nights. She is invited to bring in her wealth of noble values to nourish and purify the cleansed mind. Finally Goddess Saraswati is invoked on the last three nights to bestow the Higher Knowledge of the Self-possible only after cleansing and purification have taken place. With the dawn of spiritual wisdom the little ego is destroyed. This destruction is commemorated on the 10th night with (by) the burning of an effigy. This 10th day is called Vijayadashmi (Vijaya-victory,dashmi-ten); or Vidhyarambha (Vidhya-wisdom, knowledge, rambha- joy) Victory Day or the Joy of Enlightenment respectively.
Why is the Navaratri Festival celebrated at night? The spiritual message of night-time worship is that “you have lived long enough in the sleepy realm of tamas, it is time to get up now. Please, wake up!!”
Basically the first three days are for Durga, the second three days are for Lakshmi and the third three days are for Saraswati. Let me tell you the basic idea behind this. It is not just Durga, Lakshmi and Saraswati, but Shakti, Prosperity and Vidya. If you go still deeper, a lot of other things are added to it and it requires a lot of time to write in detail about all that.
Now about the Nine Days Puja, the deities are as follows;
1. Skanda Mata - Goddess of Fire.
2. Kusumanda (or Kuchamanda) - Goddess of Solar System.
3. Sailaplutri - Goddess of embodiment of power of Trimurtis.
4. Kalaratri - Remover of darkness (ajnana), giver of freedom from
fear, adversities, death, etc.
5. Brahmacharini - Giver of moksha
6. Mahagowri - 8 year old girl - Giver of peace - She is the peace
component of Durga.
7. Katyayani - Goddess of Vatsalya, Love, etc. (Goddess of Brindavan)
8. Chandraghanta - Apostle of bravery, drives away evil doers and
demonic incarnations.
9. Siddidhatri - Giver of siddhies, bestower of accomplishment /
achievements and ultimately moksha.