Saint Symeon the New Theologian.
That one should not embrace and zealously observe the benefit of the fast only in the first week of Lent, but that the zealous must continue the same zeal in all the weeks of Lent.
The first week of lent.
Brethren and fathers, what we are about to say we ought to have addressed to your charity last Sunday. I was aware, however, that everyone of us believers, [together with] the whole Christian people, both monks and laity, with fervent zeal accepts the blessing of fasting in the holy first week of Lent, and that each one of us willingly puts its yoke upon his neck (Sir. 51:26). Even among those who greatly despair of their own salvation and live their lives without fear and reverence for God there is no one who rejects the law of fasting in that week. Rather, as far as he is able, he joins with all in observing abstinence. So I come today to speak a few short words to you about the present season.