Human's destiny after death in Buddhism.
Is there an afterlife? People often think that it is not important to think of the after/future life, they believe that we should live life to the fullest, focus on the moment, focus on how to improve life now, and gasp as much pleasure and enjoyment while we can. They believe that thinking of the afterlife is a waste of time. However, it is essential to gain some understanding of the complete context in which our life unfold. Not to remain content just to live in ignorance. Our view will influence our action, if one believe that the afterlife is imaginary then it makes sense to enjoy the worldly life much as possible. On the other hand, if we accept the idea life after death, then that will influence our conduct in our current life--we strive to be better and practice Buddhist doctrine more effectively. There's another possibility that once a person die, the physical make-up will decompose and the person is no more, a state of nothingness. Or in the Christianity/Islam view, once we die we go to heaven and live there eternally. Or in the Hindu/Buddhist view, a person will rebirth, transmigrate from one life to the next.
What is it that causes us to take rebirth in some form? What is it that determine the form of rebirth we take? The answer for this the Buddha gives is : Karma. Karma will determine what type of person we are, and how we undergoes in the course of our life. However unintentional action is not Karma. For an example, if a person steps on ants while working out on the street, then that is not Karma, because one did not have the intention of taking lives. Or if someone said something that they believing to be true, when it is false, then that person is not to blame for the Karma of lying. Since that person did not have the intention of lying. Karma manifests itself in three ways: body, speech, and mind. When we act psychically, the body serve as the instrument for expressing ourselves, that is body karma. When we speech, express our thought and intention, then that is our speech Karma. When we think desire inwardly, without any outward action, that is mental Karma. People often mistaken that bad things that is happened to them in the present is Karma, but that is not Karma, rather that is the effect or fruit of their karma. If they run into a lot of trouble they say "oh that's Karma," but that is not Karma, karma is the active force, the present action. Many of the troublesome situation people find themselves in is a result of their past Karma.
Good karma will bring good result; i.e prosperity, beauty, wisdom, long life, health,
Bad karma: ugly, poverty, suffering, etc..
In on of the Sutra, Buddha gives some examples:
The reason why some people die prematurely, in the past they destroyed life--the karma of killing is short live. Other people long life, on previous life they were kind and compassionate. Some people are very sickly; in the past they injured and hurt other. Some people are always healthy, these people always help others. Those who often angry in the past, they are ugly. Those who are patience and cheerful, they become beautiful. Some are rich, these people who were generous int he past. Some are poor, these were the ones who are self indulged. Some are influential; these were the one who were rejoice in the fortune of others. Some are weak and powerless; these were the people who were evenness of the fortune of others. Some are intelligent, these were the one that reflect and study in the past. Some are stupid, these were the one that were lazy and did not study in the past. According to the Buddha, each Karma products a result corresponding to its merit.