In this way, we will have a spiritual sense that makes us distinguish and discern the spirit. Masters of spiritual life always recommend good spiritual readings. God talks to us through good reading. It sharpens our spiritual sense and we can become familiar with the language of God. As man becomes saturated by secular mentality through the media simply because he is constantly bombarded by it, so the soul who is constantly immersed in divine thoughts through reading becomes so familiar with divine language.
Experience is the best teacher.
It trains the soul in discernment in so far as one had traversed similar situations. No wonder that the best spiritual directors are those who have lots of experience in the spiritual life. Ordinarily, the ideal one is older in age. The spirit of self sufficiency is an obstacle, which makes us look on our own decisions as always right. St. Teresa of Avila would even ask St. John of the Cross in matters of her vision when she was in her 50's and John in his 25th year.