S N Goenka retells the Tamonata sutta (AN 4:85)

The Buddha said: “I see four types of people in this world. The first type is running from darkness towards darkness. The second is running from brightness towards darkness. The third is running from darkness towards brightness. And the fourth is running from brightness towards brightness.”

The Buddha did not speak in riddles. His teaching is clear and well-explained. Svākkhāto bhagavatā dhammo. Whenever he said something that people might not understand properly, he explained it immediately. What is darkness? What is brightness? How does one keep on running from one to the other?
1. From darkness to darkness:
All around there is darkness, a life of darkness, a life of misery. One is suffering in different ways—physically, mentally, materially and because of problems in the family or society. There is no happiness at all. And yet, there is no trace of wisdom within. So every moment, this person is generating nothing but anger, hatred and ill will.

“I am suffering because of this person, because of this incident, because of this cause.” One generates aversion towards that person or cause. This misery is the result of past kammas of aversion, and now, one is planting more seeds of aversion. There is already so much darkness in one’s life and one is planting more seeds of darkness. These seeds of anger, hatred, ill will bring nothing but misery in the future. So the future will also be full of misery. The present is misery, the future is misery. The present is darkness, the future is darkness. So such a person is running from darkness to darkness.

2. From brightness towards darkness:
There is brightness all around in one’s life. There is happiness today because of material wealth, good health and prestige in society. But there is no wisdom within. So one becomes arrogant because of all this wealth, power and status and feels contempt for others.

“These poor people are all useless. I am so smart; I have got so much money, position, power, status.”

Because of some good kammas of the past, there is brightness all around. Sooner or later, this will come to an end. But every moment, one is planting seeds of egotism, seeds of aversion, seeds of misery, seeds of darkness. These seeds of negativity will result in darkness in the future, misery in the future. Thus this person is running from brightness towards darkness.

3. From darkness towards brightness:
The third type of person is in exactly the same position as the one in the first group. There is hardship all around, darkness all around in the present but there is wisdom inside. One keeps on smiling.

“Oh, this hardship has come because of some past bad kammas of mine. Somebody seems to be the apparent cause of my misery. Certainly, this person is not the real cause of my misery. This person has just become a vehicle. May he or she not have to suffer because of these misdeeds! This hardship was bound to come through this person or through some other person because of my own past kammas. Now I will not plant new seeds of misery.”

So one generates only love and compassion towards such people. One is planting seeds of love, of compassion. Now there is darkness, but the future is full of brightness. Sooner or later this darkness will go and then there will be only brightness. One is planting seeds of brightness, which will bring brightness in the future, happiness in the future.

4. From brightness towards brightness:
At present, one’s life is filled with brightness, filled with happiness. One enjoys the happiness of material wealth, all worldly comforts, and prestige in society. But there is wisdom and one keeps on understanding:

“All this success is because of some good kammas of the past. And whatever good kamma I might have done, they are not eternal, their fruit is not eternal, sooner or later it will come to an end. So, I must make best use of all this money, position, power, status that I have now for the good of others. As a householder, it is my duty to use my wealth for the maintenance of my family and those who depend on me. Whatever remains, I must use for the good of others, for the benefit of others. May more and more people get pure Dhamma! May more and more people develop wisdom! May more and more people be liberated from their suffering!”

So one generates love, compassion, and goodwill all the time. All actions—vocal, physical, and mental—are for the good of others. One plants seeds of brightness. From happiness one is running towards happiness; from brightness, one is running towards brightness.

We should not be like the people in the first or the second group. We must be like the people in the third or the fourth group. Whether third or fourth, this is not in our control. Sometimes, life may be full of darkness, full of suffering because of the past kammas. At other times, life may be full of brightness because of the past kammas. There is happiness or unhappiness in life because of the results of past good and bad kammas. Irrespective of whether there is happiness or sorrow, brightness or darkness, we will develop brightness within.