Upon performing a close reading of "The Lottery" we find that the villagers have little to no knowledge of what exactly it was, what it was for, nor why it was still being conducted. We find evidence of this in the part of the story which reads,

some people remembered, there had been a recital...performed by the official of the lottery, a perfunctory, tuneless chant that had been rattled off duly each year... the official of the lottery used to stand just so when he said or sang it, others believed that he was supposed to walk among the people, but years and years ago this p3rt of the ritual had been allowed to lapse.

This implies that the people duly followed a tradition that nobody has bothered to even follow with enough care and respect to remember each and every one of its goals and purposes. We hear "traces" of knowledge; one chant, perhaps a formal salute, a few changes to the format, etc. Aside from the format of the tradition, we see no important content; there is no substance to the matter and moreover there is only one flimsy explanation in the entire story and it is that

there’s been a lottery for seventy-seven years"

and that any attempt to change things would be ridiculous.

However, Old Man Warner who has seen over the lottery for the seventy years of his life without getting picked, provides a clue as to what the origins of the lottery once were.

Used to be a saying about 'Lottery in June, corn be heavy soon.' First thing you know, we'd all be eating stewed chickweed and acorns. There's always been a lottery

Therefore, that there was once a purpose and reason for the lottery to exist is evident. They sacrificed one of their own to secure rain and good crops. However, it is also evident that they have maintained a tradition that is based on fallacy for no real reason. No mention of the crops nor the rain is made except for Old Warner.

There is a note to make, however, and it is that there seems to be an underground feeling of rejection toward the lottery that may indicate the beginning of change. Notice how Mr. Adams says that

over in the north village they're talking of giving up the lottery

to which the Old Man Warner responds,

Listening to the young folks, nothing's good enough for them. Next thing you know, they'll be wanting to go back to living in caves, nobody work any more, live hat way for a while.

Combine that with Tessie's final words "it's not fair", and we get a clear picture: the people merely follow the status quo without question, even though deep inside they are as scared and against the practice as anyone else could be. It is a message to the reader: beware of the practices followed out of habit; they can actually lead to our moral, personal, physical, or social death.

The exact purpose of the lottery is nebulous, but apparently it was started as some sort of superstition-based ceremony to ensure crops would grow and produce a sizable yield. Now, it has simply become a ritual the townspeople blindly follow, and those who have an innate proclivity for violence take delight. 

There is truly a sense of blind adherence to tradition in the members of the community. They gather together and "their jokes were quiet and they smiled rather than laughed." When a late Mrs. Hutchinson makes her way through the crowd toward her husband, "[T]he people separated good-humoredly to let her through." Mrs. Hutchinson excuses herself by saying to the man in charge of the lottery, "Wouldn't have me leave m'dishes in the sink, now, would you, Joe?"

When it is time to start the lottery, Mr. Summers says soberly, "guess we better get started, get this over with, so's we can go back to work." As Mr. Summers calls names out, Mr. Adams remarks to Old Man Warner, "They do say. . . that over in the north village they're talking of giving up the lottery." Mr. Warner snorts in disgust and says,

Pack of crazy fools. . . Listening to the young folks, nothing's good enough for them. Next thing you know, they'll be wanting to go back to living in caves, nobody work any more, live that way for a while. Used to be a saying, 'Lottery in June, corn be heavy soon.' First thing you know, we'd all be eating stewed chickweed and acorns. There's always been a lottery.

Then, there are those who simply delight in the violence of the lottery. Before Mr. Summers arrives, Bobby Martin, Dixie Delacroix, and the Jones boys stockpile stones so they have enough ammunition to throw when it is time. Even Mrs. Delacroix, who has spoken in a friendly manner to the victim, Tessie Hutchinson, tells her to "be a good sport" after she is selected. Shortly after saying this, Mrs. Delacroix "selected a stone so large she had to pick it up with both hands." She tells Mrs. Dunbar, "Come on. . . Hurry up!"

The lottery which has been going on for at least 77 years as Old Man Warner tells us, is for the purpose of human sacrifice.  Each year, in June, the town holds a lottery, a selection process, whereby each family chooses from the black box, a slip of paper.  If your family is unlucky enough to select a slip of paper with a black dot, then your family is chosen. 

Then your family members, children included must choose from a group of slips of paper to determine which member of the selected family will be sacrificed.  The winner of the lottery is stoned to death by the other members of the town who display little or no sympathy, mercy, compassion or interest in the death of one of their neighbors. 

What is so striking about this short story is that the author, Shirley Jackson, allows the reader to believe that the lottery is accepted by the townspeople the same as a dance, or picnic.  It is a deeply held tradition embedded in the culture of the town. 

No one can remember what the original reason for the lottery was, they can't remember the ceremonial songs that were part of the ritual, but they keep holding the lottery anyhow.

Fear that their crops will not be full and hearty is suggested as one reason for the lottery.  Some ancient cultures believed that human sacrifice satisfied the gods and therefore, the village would be granted a plentiful harvest in return. 

One is sacrificed so that many may live.  

Old Man Warner reveals the closest answer possible to this question. He comments:

"Used to be a saying about 'Lottery in June, corn be heavy soon.' First thing you know, we'd all be eating stewed chickweed and acorns. There's always been a lottery,"

This use of a tired out phrase that is only remembered well enough to be shard by the seemingly oldest character in the group illustrates both the message of the entire story and the purpose of the lottery originally. It seems that the purpose had to do with the fact that people once believed if someone was sacrificed in this manner, the corn crop would come in strong. The message of this story has to do with doing something just because that's how it's always been done. The absurd message drives audiences to the point of horror making them consider their own ways.