Musar על ברכות 33:9

On this matter it was said: "a person should always be clever in the fear of Heaven" (Berachot 17a) - to know and deduce one thing from another, and to devise new ways of bringing gratification to his Maker in every possible manner.

Since the nature of a man's heart is to become proud and haughty, it is difficult for him to root out this natural tendency at its source. But by performing external actions that are under his control, he will slowly, slowly draw in his inner being the matter which is not so much in his control. This is similar to what we wrote in Zeal. All this is included in the statement of our sages, of blessed memory, "a man should always be cunning in the fear of heaven" (Berachot 17a), namely, that one seeks out strategies to employ against his nature and tendencies until he vanquishes them.