The explanation in terms of Kamma of why the enterprises of some individuals fail, while others turn out differently than expected, others turn out as expected and still others turn out beyond their expectations.
Read the Sutta
Index to available translations: AN 4.79
In the Pali, Sariputta asks
"Ko nu kho bhante hetu ko paccayo ~"
Woodward translates "what is the reason what is the cause"
Usually 'hetu' is translated 'cause'; when you read 'cause' in translations, look up the Pali, if the Pali is 'hetu' think 'driving force' 'engine';
if it is 'nidana' think 'bound up with' or 'bound down by';
if it is 'paccaya' think 'dependence', 'condition'.
Bhk. Bodhi just has "why", or "the reason why".
A translation more helpful in understanding the meaning would be "What is the driving force, what results in these various experiences?" Of the many factors that go into success and failure in one's occupation, what is the one which is most determinant of the outcome?
The Buddha uses a gift to a shaman or brahmin as the example, but the same dynamics are at work with any person.
Be careful of what you promise!
Don't make promises you cannot keep.
Make every effort to fulfill promises you have made and if you can see you will be unable to do so, get back to the person to whom the promise was made and make an explanation.
Take a care for your future happiness! The feelings of the person expecting the fulfillment of a promise you have made are your feelings later.
Woodward footnotes Points of Controversy where an objection is made to the whole proposition that there is such a tie between the giver and receiver based on the notion that since the individual is continuously changing, he cannot be said to be the same person from one minute to the next so that for him there is no return on a gift. A sort of madness that comes from getting high understanding only half the picture.
In this case the person has understood the idea that there is no thing there that can be called the self and has come to the conclusion (formed the opinion, arrived at the point of view) that there is no self.
It is vital to understand the Buddha's position with regard to subjective experience in order to understand why it is not correct to say that there is no self.
There is the subjective experience of a continuing self.
Until liberated from that by the understanding that it is not a true perception, that it is only identification with a point of view, that subjective self experiences suffering.
ḌIf that were not the case, what would be the point of Buddhas or their Dhamma?!
The Buddha's teaching is for the relief of that subjective suffering as well as for the complete liberation from it. Gotama's teaching is for the liberation from Pain. All Pain. Real or imagined.