“He who is satisfied with himself, smug in his proper performance of mitzvot and the correctness of his life, may be somewhat perturbed by the injunction to be humble before all men, irrespective of who they are.
He has to compare himself in subjective terms:
Does he, indeed, struggle with himself to the same degree he requires of the most casual delinquent?
Can he put himself in the others place and overcome the same temptations?
There is the story of the Tzadik who, after passing through a forest, said that he was amazed at the awe and fear of God he had seen displayed by some nameless person there.
An uncouth and unlearned youth had been standing among the trees, shouting at his father:
‘Were I not afraid of God I would smash your head with my axe!’
This indicated, said the Tzadik, that the youth had overcome a powerful urge to kill his father and had done so because of a genuine fear of God.
‘Such a victory,’ said the Tzadik, ‘is more than I can claim for myself, never having struggled with such a terrible passion; and I am humbled by it — not at all sure whether I, or those around me, would be able to make the same sacrifice.’ “
From “Critical Insight into Oneself,” p. 201-202, in The Long Shorter Way by Rabbi Adin Steinsaltz