Out of everything that we ask God, He fulfils only what is truly necessary, as a mother who does not do everything that her child wants, but only that what makes him happy.

Prayer is never lost, even if God fulfils it or not! And it is natural that He may not always listen our prayer, because often we ask for useless things. And then, valuing the effort of our prayer he bestows upon us, even without us noticing them, any valuable and useful things.

(Translation from: Sfântul Teofan Zăvorâtul, Călăuzire către viața duhovnicească, traducere de Preot Victor Manolache, Editura Egumenița, p. 66)