9. In truth, this is the secret. We learned that it is written: "We remember the fish, which we did eat in Egypt for nothing" (Bemidbar 11:5), MEANING "FOR NOTHING," without a blessing, as we did not have a heavenly yoke in Egypt. Come and behold: slaves are exempt from the yoke of the Kingdom of Heaven, and so they are exempt from the commandments. What is this the yoke of the Heavenly Kingdom? It is like an ox upon which they first place a yoke in order to work with him and draw benefit from him for the world. If he does not accept that yoke he does no work at all. So man must accept upon himself the yoke OF THE HEAVENLY KINGDOM first, and then he will toil with it all that he needs. However, if he does not accept this yoke upon himself first, he cannot work.
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).
11. And this yoke cannot rest upon one who is attached to another, and so slaves are exempt from the yoke of the Heavenly Kingdom, BECAUSE THEY ARE TIED TO THEIR MASTERS. If they are exempt from this yoke, they are exempt from all other COMMANDMENTS, since other COMMANDMENTS are not placed upon one until this yoke is with him. Therefore, Yisrael in Egypt ate without cost. Here too, "he shall go out free" (Shemot 21:2), since he was a slave and whatever he did was without cost, without the yoke of the Heavenly Kingdom. So even though his deeds were for nothing, "he shall go out," and find rest. THE EXPLANATION OF THE VERSE IS AS IF IT SAID, 'FOR FREE YET HE SHALL GO OUT.'