Even as a speck of dust, so is the improper thought in the heart of man.
Often, we do not consider the thoughts and ideas that attract us. We do not reason regarding their propriety, wholesomeness, and usefulness. Accepting the enemy’s suggestions indiscriminately, we suffer harm; often little, but at times great harm, maleficent or altogether deadly for the soul. The picking of mushrooms could serve as a good example in this case.
Certainly, everybody knows that one has to pick mushrooms very carefully in order not to get poisoned while eating them. There are obviously poisonous mushrooms: toadstool, fairy-mushroom; there are also much more dangerous mushrooms: the false ones. They look very much like the edible ones, but in reality are poisonous. The experienced pickers examine all the mushrooms very carefully before placing them in the basket. If there is a slightest shadow of doubt as to whether a mushroom is edible or not, they throw it out.
In order to avoid pernicious harm to the soul, one must act much in the same way with all thoughts, desires, and ideas. All thoughts that are from God, ones that are pure, penitential in nature, humble, and filled with love toward God and one’s neighbor, should be accepted and placed in the basket of the heart. All thoughts from the enemy, those that are proud, cruel, self-centered, self-loving, evil, malicious, and others like unto them, must be thrown out.
The eyes are washed with pure water or a medical solution. In the same way, the heart must be cleansed by prayer and protected from the dirt of improper thoughts, in order for it always to be able to see the Lord and His light clearly, in order for it to be a temple worthy for the dwelling of the Holy Spirit.