John Cassian

For among them (the Egyptians) these offices, which we are taught to render to the Lord at separate hours and at intervals of time with a reminder from the convener, are celebrated freely and continuously throughout the whole day in conjunction with their work. For manual labor is continuously practiced by them in their cells in such a way that meditation on the Psalms and the rest of the Scriptures is always before them. To this at every moment they mingle short petitions and prayers, spending the whole day in those offices which we celebrate at fixed times. Thus, except for vespers and nocturns, there are no public services among them in the day except on Saturday and Sunday, when they meet together at the third hour for the purpose of Holy Communion. For what is continuously offered is greater than what is rendered at intervals of time. And a free gift is more acceptable than the duties which are performed by the compulsion of a rule. For such as this, David rejoices somewhat exultingly when he says, "Freely will I sacrifice to you;" and, "Let the free will offerings of my mouth be pleasing to you, O Lord."