A short explanation of what Diwali is, taken from here, a non-Sahaj website.
This is perhaps the most well-known of the Indian festivals: it is celebrated throughout India, as well as in Indian communities throughout the diaspora. It usually takes place eighteen days after Dusshera. It is colloquially known as the "festival of lights", for the common practice is to light small oil lamps (called diyas) and place them around the home, in courtyards, verandahs, and gardens, as well as on roof-tops and outer walls. In urban areas, especially, candles are substituted for diyas; and among the nouveau riche, neon lights are made to substitute for candles. The celebration of the festival is invariably accompanied by the exchange of sweets and the explosion of fireworks. As with other Indian festivals, Diwali signifies many different things to people across the country. In north India, Diwali celebrates Rama's homecoming, that is his return to Ayodhya after the defeat of Ravana and his coronation as king; in Gujarat, the festival honors Lakshmi, the goddess of wealth; and in Bengal, it is associated with the goddess Kali. Everywhere, it signifies the renewal of life, and accordingly it is common to wear new clothes on the day of the festival; similarly, it heralds the approach of winter and the beginning of the sowing season.
November 12th, 2007
The lights of your heart together make a greater light for the world to move in a proper direction. It's a day of great joy, and those who join in this, are spreading also great joy.
But the problems are there, as they say, but for us there is no problem because there is no darkness. We don't see any darkness anywhere; we see lights, and lights, and lights.
Then what is the thing missing? Missing is our sincerity. We have to be very sincere with ourselves, because it is not just a borrowed love or borrowed joy, but it is from within the source; it's flowing and flowing and flowing.
So that is to be awakened, and that love should flow, and our small petty things like jealousies and competitions and all those things which spoil us, must be washed away. And it can be washed if your heart is full of love. Today is a day of spreading that light of love, so that everybody feels enlightened and happy and forgets these petty problems…
You are already blessed people; there is no doubt about it. And we should not worry about small things and small matters. It will all work out very well, you will see, if you just leave it to your destiny, which is very high, very great - in this your own destiny you will go very far.
This is the Promise of Diwali to you all, that you will reach the highest and the noblest way of life.
Every word I say will be there to prove what I say is there. Whatever petty problems you have, they'll all be washed off. All these are the messages from the Divine. You don't have to worry about petty things, about money, about jobs. That's not your job. Your destiny will work it out. You have a promise that you'll be looked after. I hope you believe in that promise and are joyous in the highest way. I bless you all from my heart, all of you, for a very happy and prosperous Diwali. Thank you very much.
Shri Mataji, Diwali 2003
Taken from http://www.sahajayoga.com.au/news/2007/11/12/a-diwali-message/