The Midrash doesn't say much about Japheth,except to note that he didn't take the lead in covering his drunken father, even though he was the older brother. Noah's blessing of Shem and Japheth implied that the Divine Presence would dwell in the Temple built by Shem's descendant Solomon, but not in the Second Temple, which was built by Japheth's descendant Cyrus.
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