From what I understand of the Buddha's time (correct me if I'm wrong)
there were Brahmans. The Brahmans believed that when you die you could be reborn in various places ie. the hells, or heaven. The Buddha naturally catered his teaching to the beliefs of the people of that time. However, he stated in a text (I forget which one) "If you believe in rebirth in the hells than..." The key word here is "If". I see if I can dig up that text.
Anyway, the Buddha had an awakening when he (there might be different versions) notice a plow man was plowing a field. The plow man dug up the earth and there was a worm. A bird swooped down and ate the worm. Thus the action of the plow man had a result . The saw that everything is attached in this way. Cause and effect. I think Kamma is an important teaching to understand.
The Buddha said (or it was written):
"Bhikkhus, what is the way leading to the cessation of kamma? This is the Noble Eightfold Path, namely, Right View ... Right Concentration. This is called the way leading to the cessation of kamma."
"Bhikkhus, this body does not belong to you, nor does it belong to another. You should see it as old kamma, formed by conditions, born of volition, a base of feeling."
This practice of dropping body and mind moment to moment and being mindful of what is happening is the road to ending this round of good and bad Kamma. Some might call it ceaseless practice. Everything that we do has an effect. Sometimes a good effect and sometimes not. If we eat too much we might get sleepy. If we get sleepy we might not feel like doing the dishes. If we don't do the dishes cockraoches might gather or someone else will have to do them. There are infinite possibilities to the results of our actions. Through practice we have the capacity of understanding this is within our reach. If we just do what needs to be done without thinking about right or wrong. The eight fold path is there. It is to be used. There are no exceptions to the rule. Live a good simple life. Be mindful, do the dishes, wish others happiness and joy, gain compassion and understanding through sitting, realize that this body and mind that you think is yours really isn't and that because it is not yours you should treat it with respect. Go to bed on time. Do your chores and if you don't have a house to do chores in then use the understanding that you have gained from your practice. Understand nonattachment. Realize that this little piece of rock that we live on that gets warmth from the sun, could at any minute be destroyed by an astroid or any other natural occurance. Earthquakes, Typhoons, Floods, Volcanoes, Tornadoes, are all nature's way of telling us that all things come and go. That they are impermanent. Kamma goes on and on, and it seems that we human beings are the one things on the planet that can change it so drastically. The Ozone, pollution, waste, war. Through practice we can't ignore the fact that there is Kamma and what we do "does" have an effect on everything that we come in contact with. We might not know the results of our action, but let your wisdom guide you.
As I sleep this night
may all beings calm all things
and discover the true mind of clarity