"From this it follows that all methods or exercises for kindling and preserving the spirit of zeal can be briefly stated thus: after awakening, go with in yourself, stand in your place in the heart, go through all the spiritual life activities and, stopping with one or another, remain there without leaving. Or, even more briefly: gather yourself and instruct yourself secretly in the heart.
"By this method, with the help of the Lord's grace, the spirit of zeal in its true tone will be upheld, even warmed and flaming. This is the inner way. Note that this is the most direct path to a salvific disposition. One could abandon everything and practice only this activity, and everything would go successfully. On the contrary, even if we think to do everything else but pay no attention to this, we will see no fruit.
"He who does not turn within and ignores the spiritual activity only delays the work. True, this work is extraordinarily difficult in the beginning, but it is direct and fruitful. This is the why a guiding priest must as quickly as possible lead his spiritual children into this work and confirm them in it. He could even leave then in it first of all externally, but he should comply with it however he can – and he not only may but should do this. This is because the seed for this activity was planted at conversion, during which all of this was experienced. It is left only to explain it, interpreted as something important, and lead them through it. Then the external part will also go smoothly, quickly and rightly. However, without this the external alone, like rotten threads, will all fall apart. Note the rule that it must not be done suddenly, but by degrees. Great limitations should be placed on it, for it may not lead to this inner work, which is the essential work, but to external rules. Therefore, regardless even of the fact that there are people who go from the external to the internal, this should remain an irrevocable rule -- to go quickly within and there enkindle the spirit of zeal.
"It would seem to be a simple thing; but not knowing about it you can labor at it for a long time, with very little fruit. This is because of the nature of bodily activity. It is easier, and therefore becomes a habit, while the inner work is difficult, and therefore is pushed away. But if you become attached to bodily labors as to the material world, you will yourself become material in spirit and therefore cold, slow, and consequently, more and more removed from the interior world sometimes it happens that one abandons the interior work at the very start, as if waiting until he has become ripe for it. The time comes, but afterwards he looks around, and the time has passed; and instead of preparing himself for it he has become completely incapable. Again, the external should also not be neglected, for it supports the internal, but both should proceed jointly. It is obvious that only the internal should predominate, for we should serve God in spirit and worship him in spirit and in truth. One and the other should be in mutual submission according to each one's measure of worthiness, without doing violence to one another or causing compulsory separation" (St. Theophan the Recluse, The Path of Salvation, pp. 237-238).