This is the mark of Christianity: however much a man toils, and however many righteousnesses he performs, to feel that he has done nothing, and in fasting to say, “This is not fasting,” and in praying, “This is not prayer,” and in perseverance at prayer, “I have shown no perseverance; I am only just beginning to practice and to take pains “; and even if he is righteous before God, he should say, “I am not righteous, not I; I do not take pains, but only make a beginning every day.

[Abba Macarius the Great, Homily 26]