"If you see a man proud and puffed up because he has a share of grace, this man, even if he should work miracles and raise the dead, but does not hold his soul worthless and contemptible, and continue poor in spirit and an object of abhorrence to himself, is cheated by sin without knowing it. Even if he works signs you cannot believe him, for the sign of Christianity is this, to be approved of God while earnestly shunning the notice of men, and even if a man has the entire treasures of the King, to conceal them, and to say continually, " It is not mine; another has put this treasure in my charge. I am a poor man, and when He pleases, He takes it from me." If any one says, "I am rich; I have enough. I have gained; I need nothing more," he is no Christian; he is a vessel of error and of the devil. The enjoyment of God is insatiable. The more any one tastes and eats of Him, the more he hungers. Such men's ardour and passion for God is beyond restraint, and the more they endeavour to get on and make progress, the more they esteem themselves poor, as those that are in need and have nothing. This is what they say: " I am not fit for this sun to shine upon me." This is the sign of Christianity, this humility."
- Saint Macarius the Egyptian
Reference: http://www.archive.org/details/fiftyspiritualho00pseuuoft