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What are "Matzvos Beis Shemesh"?
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Rashi: They are the altars that they made there, those who converted in the days of Chizkiyah, i.e. Sancheriv's captives from Kush and Egypt. He brought them in front of Yerushalayim on the day of his downfall - "ba'Yom ha'Hu Yihyu Chamesh Arim b'Eretz Egypt Medabros Sefas Kena'an v'Nishba'os la'Shem Tzevakos Ir ha'Heres Ye'amer l'Echas" (Yeshayah 19:18 1 ). Targum Yonasan there says 'the city Beis Shemesh, which in the future will be widened, it will be said that it is one of them.' 2
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Rashi (Yeshayah 19:18): Chizkiyah freed the captives. They accepted the yoke of Shamayim and returned to Egypt. They built a Mizbe'ach and offered to Hashem.
