Origen

“ For it is impossible for man, who is a compound being, in which “the flesh lusteth against the Spirit, and the Spirit against the flesh,” [6] to keep the feast with his whole nature; for either he keeps the feast with his spirit and afflicts the body, which through the lust of the flesh is unfit to keep it along with the spirit, or else he keeps it with the body, and the spirit is unable to share in it. ”

“ But the majority of those who are accounted believers are not of this advanced class; but from being either unable or unwilling to keep every day in this manner, they require some sensible memorials to prevent spiritual things from passing altogether away from their minds. ”