“The sins of thought are not an unimportant matter for the Christian, because all that is pleasing to God in us is comprised, according to Saint Macarius of Egypt, in thoughts, for the thoughts are the beginning from which words and deeds proceed : words, because they either benefit those who hear them or are corrupt and tempt others, perverting their hearts and thoughts; and deeds, still more, because examples act more powerfully than anything upon people, inciting them to imitate them.”

(St John of Kronstadt, ‘My Life in Christ’)