The Buddha's insight into karma - actions have consequences

Taken from the Dvedhavitakka Sutta, Majjhima Nikaya 19, http://www.accesstoinsight.org/tipitaka/mn/mn.019.than.html

Siddhartha Gautama (the future Buddha) is sitting in meditation prior to his enlightenment. This excerpt describes his insight into the workings of karma (here: kamma): how we suffer or experience happiness as a result of the states of mind in which we act.

"When the mind was thus concentrated, purified, bright, unblemished, rid of defilement, pliant, malleable, steady, & attained to imperturbability, I directed it to the knowledge of recollecting my past lives. I recollected my manifold past lives, i.e., one birth, two... five, ten... fifty, a hundred, a thousand, a hundred thousand, many eons of cosmic contraction, many eons of cosmic expansion, many eons of cosmic contraction & expansion: 'There I had such a name, belonged to such a clan, had such an appearance. Such was my food, such my experience of pleasure & pain, such the end of my life. Passing away from that state, I re-arose there. There too I had such a name, belonged to such a clan, had such an appearance. Such was my food, such my experience of pleasure & pain, such the end of my life. Passing away from that state, I re-arose here.' Thus I remembered my manifold past lives in their modes & details.

"This was the first knowledge I attained in the first watch of the night. Ignorance was destroyed; knowledge arose; darkness was destroyed; light arose — as happens in one who is heedful, ardent, & resolute.

"When the mind was thus concentrated, purified, bright, unblemished, rid of defilement, pliant, malleable, steady, & attained to imperturbability, I directed it to the knowledge of the passing away & reappearance of beings. I saw — by means of the divine eye, purified & surpassing the human — beings passing away & re-appearing, and I discerned how they are inferior & superior, beautiful & ugly, fortunate & unfortunate in accordance with their kamma: 'These beings — who were endowed with bad conduct of body, speech & mind, who reviled the Noble Ones, held wrong views and undertook actions under the influence of wrong views — with the break-up of the body, after death, have re-appeared in the plane of deprivation, the bad destination, the lower realms, in hell. But these beings — who were endowed with good conduct of body, speech, & mind, who did not revile the Noble Ones, who held right views and undertook actions under the influence of right views — with the break-up of the body, after death, have re-appeared in the good destinations, in the heavenly world.' Thus — by means of the divine eye, purified & surpassing the human — I saw beings passing away & re-appearing, and I discerned how they are inferior & superior, beautiful & ugly, fortunate & unfortunate in accordance with their kamma.

"This was the second knowledge I attained in the second watch of the night. Ignorance was destroyed; knowledge arose; darkness was destroyed; light arose — as happens in one who is heedful, ardent, & resolute."