A living body is in constant formation and deformation and subject to disintegration; therefore it cannot be eternal. Eating and drinking are for the perpetuation of the individual and sexual relations are for the perpetuation of the species. These are fundamental to the worldly life but there is no need for them in the world of eternity. So why have they been included in the greatest pleasures of Paradise?
Firstly a living body is doomed to decline and death because of the imbalance between what it takes in and what it consumes. From childhood to the age of maturity what it takes in is more than it expends. Afterwards its expenditure increases until it results in the destruction of the balance and death. In the world of eternity however the particles of the body remain constant and are not subject to disintegration and reformation. Or the balance between the body's income and consumption remains constant.2 Like moving in perpetual cycles a living body gains eternity together with the constant operation of the factory of bodily life for pleasure. Although in this world eating drinking and sexual relations between married couples arise from a need and perform a function a great variety of excellent pleasures are ingrained in them as an immediate wage for the functions performed which are superior to other pleasures. Since in this world of ailments eating and marriage are means to many wonderful and various pleasures for sure in Paradise which is the realm of happiness and pleasures those pleasures will take on a most elevated form and with the addition to them as pleasures of the otherworldly wages for the duties performed in the world and of the need felt for them in the world in the form of a pleasant otherworldly appetite they will become an all-encompassing living source of pleasure appropriate to Paradise and eternity.
This life of the world is nothing but a pastime and a game but the Abode of the Hereafter it is all living indeed.
According to the verse all the lifeless and unconscious substances and objects in this world are living and conscious there. Like human beings and animals here the trees and stones there will understand commands and carry them out. If you tell a tree to bring you such-and-such a fruit it will bring it. If you tell a stone to come it will come. Since stones and trees will take on such an elevated form for sure and of a necessity together with preserving their bodily realities eating drinking and marital relations also will take on a form as much higher than their worldly forms as Paradise is higher than this world.