“The Holy Spirit confers true humility. However intelligent, sensible, and clever a man may be, if he does not possess the Holy Spirit within him, he cannot know himself properly; for without God’s help he cannot see the inner state of his soul. But when the Holy Spirit enters the heart of man, he shows him all his inner poverty and weakness, the corruption of his soul and heart, and his remoteness from God. The Holy Spirit shows a man all the sins that coexist with his virtues and righteousness: his laziness and lack of zeal for salvation and for the good of others, the selfishness that informs what appear to be his most unselfish virtues, the crude self-love that lurks where he nevers suspected it. In brief, the Holy Spirit shows everything in its true aspect. Enlightened by the Holy Spirit, a man begins to experience true humility, distrusting his own powers and virtues and regarding himself as the worst of mankind.
The Holy Spirit teaches true prayer. No one, until he receives the Spirit, can pray in a manner truly pleasing to God. This is so, because anyone who begins to pray without having the Holy Spirit in him, finds that his soul is dispersed in all directions, turning to and for, so that he cannot fix his thoughts on one thing. Moreover he does not properly know either himself, or his own needs; he does not know how or what to ask from God; he does not even know who God is. But a man with the Holy Spirit dwelling in him knows God and sees that He is his Father. He knows how to approach Him, how to ask and what to ask for. His thoughts in prayer or orderly, pure, and directed to one object alone–God; and by his prayer he is truly able to do everything.” (Metropolitan Innocent of Moscow, The Art of Prayer, p. 232)