Most men not only bear Satan's burden willingly in their hearts, but they become so accustomed to it that they often do not feel it, and even imperceptibly increase it. Sometimes, however, the evil enemy increases his burden tenfold, and then they become terribly despondent and fainthearted, they murmur and blaspheme God's name. The usual means that men...take to drive away their anguish are...entertainments...But such means afterwards increase still more the anguish and weariness of their hearts. If, happily, they turn to God, then the burden is removed from their heart, and they clearly see that previously the heaviest burden was lying on their heart, though frequently they did not feel it.
-St. John of Kronstadt, My Life in Christ, Part 1; Holy Trinity Monastery pg.58, 19th century


The prudent farmer first clears his land of brambles before sowing it with seed. Similarly, the man who aspires to receive from God the seed of grace must first clear the earth of his heart, so that when the seed of the Spirit falls it may yield a good and abundant harvest.
-St. Makarios the Great, Homilies, VI: The Freedom of the Intellect no. 121, The Philokalia Vol. 3 Ed. Palmer, Sherrard, Ware; Faber and Faber pg. 338, 4th Century