The following homily excerpt speaks to me about the often messy discernment process which we humans have to undergo in our search for God. It is much easier to concentrate on the outside of the cup (enviromental or behavioral modifications) rather than letting our Lord cleanse us from the inside out.
Baudoin de Ford (? – around 1190), Cistercian abbot
Homily 6 on the Letter to the Hebrews, 4,12
“You cleanse the outside… Did not he who made the outside make the inside too?” The Lord knows the thoughts and intentions of our heart. For there is no doubt that he knows them all, but we only know those that he reveals to us through the grace of discernment. For a person’s mind does not always know what is inside him, and even when he is dealing with his thoughts, whether they be voluntary or not, he thinks of them in a way that does not always correspond with reality. His gaze is so darkened that he doesn’t even discern with precision those that reveal themselves clearly to his mind.For it often happens that, for some human reason or for a reason coming from the Tempter, a person sets out by means of his own thinking in something that only appears to be pious and that, in the eyes of God, does not at all deserve the reward promised to virtue.
That is because certain things can take on the appearance of true virtue, as moreover also of vice, and can deceive the eyes of the heart. Through their seductions, they can trouble the vision of our intelligence to the point that it often considers realities to be good that are in fact bad; and the other way around, they can make our intelligence see something bad where in fact there is no evil. That is an aspect of our poverty and of our ignorance that we must deplore a lot and greatly fear…Who can verify whether the spirits come from God unless that person has received discernment of spirits from God?… That discernment is at the source of all the virtues.