We sin with thought, word, and deed. To transform into pure images of the Most Holy Trinity, we must make efforts so that our thoughts, words, and actions are carriers and expressions of holiness. Thought, within God, corresponds to the Father, words correspond to the Son, and deeds to the Holy Spirit, the perfection of all.

The importance of the sins of thoughts in Christianity is not small, for in our thoughts, as St. Makarios the Egyptian testifies, lies all our pleasingness to God: For thoughts are the beginning from which our words and deeds arise; words, because they either convey grace to the listeners or are corrupt words that become a temptation for some or corrupt the thoughts and hearts of others. More than words, deeds exert influence, for example affects people more than anything else, drawing them toward imitation.

Conscience in people is nothing other than the voice of the ever-present God, Who walks within their hearts. As the One who created all things, and being One, the Lord knows everyone just as He knows Himself; He knows all their thoughts, wills, and intentions, their words and deeds, both present, past, and future. No matter how much I may rush somewhere with my thoughts and imagination, He is there before me, “Where can I go from Your Spirit, or where can I flee from Your presence?” (Psalm 139:7).

Oh! If only we could pay attention to see the consequences of our sins or our good deeds. How careful we would be then in avoiding sin, and how zealous we would be for good. If the heart is pure, then the whole person is pure. And if the heart is unclean, then the whole person is unclean. Here lies the struggle of the Christian. All the Saints, through fasting, watchfulness, prayer, and godliness, through reading the Word of God, through martyrdom, toil, and sweat, attained a pure heart, and thus the Holy Spirit dwelt within them, cleansing them from all impurities and sanctifying them with eternal sanctification.

St. John of Kronstadt