The neshama's return to heaven is
dependant upon the body's return to the ground. That is what
the Prophet means when he says,
"The dust returns to the earth...and the
spirit returns to G-D who gave it."
Jewish Law is, therefore, concerned with the
immediacy of burial and the natural decomposition of the body.
Mausoleums are forbidden since they retard the process of return to
the earth. Cremation is certainly forbidden. It is the
harshest form of indignity to the body, and is a pagan ritual that
denies the existence of G-D.
The only acceptable burial is directly in the
ground, with family members and friends helping to fill the grave
completely until a mound is formed. No attempt to retard the
body's decomposition is permitted.