John Cassian, The Institutes X.5: How the attack of accidie is twofold

And so the true Christian athlete who desires to strive lawfully in the lists of perfection, should hasten to expel this disease also from the recesses of his soul; and should strive against this most evil spirit of accidie in both directions, so that he may neither fall stricken through by the shaft of slumber, nor be driven out from the monastic cloister, even though under some pious excuse or pretext, and depart as a runaway.