Spiritual training (pneumatic gymnasia) is askesis for piety. It is most valuable, "having promise for the life that now is, and for that which is to come." The efforts made for the sake of piety bring spiritual gladness.
Theophylaktos says: "Train yourself for piety, that is, for pure faith and the right life. Training, then, and continual efforts are necessary; for he who trains exercises until he perspires, even when there is no contest."
Training accustoms one to be lenient, temperate, capable of controlling his anger, subduing his desires, doing works of charity, showing love for his fellow men, practicing virtue. Training is virtuous askesis, rendering one's way of life admirable.
Askesis is practice, meditation, training, self-control, love of labor.
Saint Nektarios of Aegina