A Christian is called to leave everything and follow Christ in poverty of spirit, becoming free of the sinful desires of this world. According to the world of the Apostle John the Theologian:
If any man love the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. And the world passeth away, and the lust thereof: but he that doth the will of God abideth for ever (I John 2:15-17).
The holy Fathers of the Church wrote very much about humility, considering that a correct spiritual life needs this virtue more than all else. Saint Isaac the Syrian, for example, writes:
The truly righteous always think within themselves that they are unworthy of God; it is known that they are truly righteous by the fact that they consider themselves wretched and unworthy of God's care, and they confess this secretly and openly and they grow wiser by this through the Holy Spirit - in order to remain in labor and straitness while they are still found in this life. (Christian Life According to the Philocalia)
Who can understand this? How can a man standing close to God consider himself to be sinful, unworthy of God's care, the least of men? The answer we find in the life of the holy Abba Dorotheus:
I remember once we had a conversation about humility, and one of the notable citizens of the city was amazed on hearing our words that the nearer one draws to God, the more he sees himself to be a sinner, and he said: How can this be? And not understanding, he wished to find out what these words mean?
I said to him: O notable Citizen, tell me, how dost thou regard thyself in thine own city?
He answered: I regard myself as great and as first in the city.
I say to him: If thou shouldst go to Caesarea, how wouldst thou regard thyself there?
He answered: As the least of the grandees there.
And if, I say to him again: thou shouldst travel to Antioch, how wouldst thou regard thyself there?
There, he answered: I would consider myself as one of the common people.
And if, I say: thou shouldst go to Constantinople and approach the Emperor, how wouldst thou begin to regard thyself there?
And he answered: Almost as nothing.
Then I answered him: So it is also with the saints: the nearer they draw to God, the more they see themselves to be sinners.
An ancient patericon (a collection of short stories about strugglers for piety) says:
The clearer the water, the more noticeable are the smallest specks in it. When a ray of the sunlight falls on a room, it enables the eye to see myriad dust particles borne in the air, which, until the penetration of the ray, were not noticeable. So also with the human soul: The more purity in her, the more heavenly, divine light falls on her, and the more does the soul notice imperfections and sinful habits in herself.
The higher a man is morally, the more humble he is, and the more clear and constant is his consciousness of his sin.