because a ba'al is rosh of the isha as also Rebbe, Melech HaMoshiach is rosh of the Brit Chadasha Kehillah, being himself the Moshi'a  Savior  of HaGuf HaMoshiach. [Bereshis 47:18; Tehillim 16:9-10; Iyov 19:25-27; Yeshayah 53:11]