St. Nilus of Sinai: He who divides his time between physical work and prayer...

'He who divides his time between physical work and prayer subdues his body by labor and moderates its disorderly demands; and since his soul, working together with the body, at last longs for a rest, it disposes it to prayer, as to something easier, and brings it to the work of prayer with fresh strength and zeal. 

For the soul finds comfort in a change of occupation and in passing from one thing to another, whereas it gets bored when occupied for long with the same thing. It becomes weary of monotony, but welcomes variety of occupations. It seems to it that, by abandoning one occupation, it is freed of all hardship, and so it comes to another with fresh strength, as though it were only now starting work.'

St. Nilus of Sinai