Why was it build?
1. The king Khufu was incarnated by the god Horus and he was the link between the Gods and his people. At his death he was transformed to the fertile God Osiris. The pyramid functioned as an object which could activate the souls of king Khufu by the power of prayers, ceremonies and spells performed by the priests. In his afterlife it was important for his souls Ka and Ba to ascend through some shafts, which pointed toward the Gods at certain stars. Together with the Gods he should secure the travel of the sun through the underworld, protect the sunrise next morning, and equally important, secure the inundation of the river Nile which was quite essential for his people, if they should survive.
2. The building of the pyramid could remove the unemployment of farmers during the inundation.
3. The rays of the sun should reflect on the surfaces of the pyramid to make the land more fertile.
4. The building of the pyramid showed the power and superiority to the people and to the neighbor countries and once for all linked the Upper Egypt in the south and the Lower Egypt in the north.According to an ancient Egyptian belief the world rose from the sea as an island called On. The pyramid might symbolize On as a creation and/or a maintenance of life either on Earth or in Heaven.
It is not verified the king Khufu was buried inside the Great Pyramid.