10. It is written: "Serve Hashem with fear" (Tehilim 2:11). What is meant by "fear?" It is as it is written: "The fear of Hashem is the beginning of wisdom" (Tehilim 111:10). This refers to the Kingdom of Heaven, AS MALCHUT IS CALLED 'FEAR,' and for this reason, it becomes the yoke of the Heavenly Kingdom. And so this is where it all starts, SINCE MALCHUT IS THE FIRST SFIRAH GOING FROM BELOW UPWARD. What proves this? THAT WE DON the hand Tfilin first, BEING THE SECRET OF MALCHUT, AND AFTERWARDS THE HEAD TFILIN, WHICH IS THE SECRET OF ZEIR ANPIN. This is because THROUGH MALCHUT, one enters the rest of holiness. If this is not found with him, the celestial holiness cannot rest upon him. For this it writes, "Thus (lit. 'with this') did Aaron come into the holy place" (Vayikra 16:3).