In any vocation at all, we must distinguish the grace of the call itself from the preliminary image of ourselves which we spontaneously and almost unconsciously assume to represent the truth of our calling. Sooner or later this image must be destroyed and give place to the concrete reality of the vocation as lived in the actual mysterious plan of God, which necessarily contains many elements we could never have forseen.
(Thomas Merton: Contemplation in a World of Action)