Musar zu Mischlej 23:4

Only that it is not the efforts (hishtadlut) that help. Rather, the efforts are necessary, but once one has put in some effort, he has already discharged his obligation and there is place for the blessing of Heaven to rest upon him, and he need not consume his days in exertion and labor. This is what king David said: "For not from the east or from the west, nor from... but it is G-d who executes judgment, [putting down one and lifting up another]" (Tehilim 75:7-8), and king Shlomo said: "Do not weary yourself to grow rich; cease applying your understanding" (Mishlei 23:4).

When we examine closely, we will find that Humility is dependent both on thought and deed. For at first, a person needs to become humble in his thoughts and only afterwards, can he conduct himself in the ways of the Humble.

Due to what he lacks: this is evident, for it is impossible for a man, whatever level of perfection he may have reached, to not have many deficiencies, whether due to his nature, or due to his family and relatives, due to certain events that happened to him, or due to his own deeds. For "there is no righteous man on earth who does good and sins not" (Kohelet 7:20). All these are blemishes on a person which allow him no room whatsoever to become haughty. Even if he has attained many virtues, nevertheless these deficiencies are enough to obscure them.