If a king dies, and his brother lives, can his brother marry the dead king's wife to raise an heir to the throne? Or would a new line of kings begin?
כִּי-יֵשְׁבוּ אַחִים יַחְדָּו, וּמֵת אַחַד מֵהֶם וּבֵן אֵין-לוֹ--לֹא-תִהְיֶה אֵשֶׁת-הַמֵּת הַחוּצָה, לְאִישׁ זָר: יְבָמָהּ יָבֹא עָלֶיהָ, וּלְקָחָהּ לוֹ לְאִשָּׁה וְיִבְּמָהּ. 5 If brethren dwell together, and one of them die, and have no child, the wife of the dead shall not be married abroad unto one not of his kin; her husband's brother shall go in unto her, and take her to him to wife, and perform the duty of a husband's brother unto her. ו וְהָיָה, הַבְּכוֹר אֲשֶׁר תֵּלֵד--יָקוּם, עַל-שֵׁם אָחִיו הַמֵּת; וְלֹא-יִמָּחֶה שְׁמוֹ, מִיִּשְׂרָאֵל. 6 And it shall be, that the first-born that she beareth shall succeed in the name of his brother that is dead, that his name be not blotted out of Israel. ז וְאִם-לֹא יַחְפֹּץ הָאִישׁ, לָקַחַת אֶת-יְבִמְתּוֹ; וְעָלְתָה יְבִמְתּוֹ הַשַּׁעְרָה אֶל-הַזְּקֵנִים, וְאָמְרָה מֵאֵן יְבָמִי לְהָקִים לְאָחִיו שֵׁם בְּיִשְׂרָאֵל--לֹא אָבָה, יַבְּמִי. 7 And if the man like not to take his brother's wife, then his brother's wife shall go up to the gate unto the elders, and say: 'My husband's brother refuseth to raise up unto his brother a name in Israel; he will not perform the duty of a husband's brother unto me.'
וַיֹּאמֶר יְהוּדָה לְאוֹנָן, בֹּא אֶל-אֵשֶׁת אָחִיךָ וְיַבֵּם אֹתָהּ; וְהָקֵם זֶרַע, לְאָחִיךָ. 8 And Judah said unto Onan: 'Go in unto thy brother's wife, and perform the duty of a husband's brother unto her, and raise up seed to thy brother.' ט וַיֵּדַע אוֹנָן, כִּי לֹּא לוֹ יִהְיֶה הַזָּרַע; וְהָיָה אִם-בָּא אֶל-אֵשֶׁת אָחִיו, וְשִׁחֵת אַרְצָה, לְבִלְתִּי נְתָן-זֶרַע, לְאָחִיו. 9 And Onan knew that the seed would not be his; and it came to pass when he went in unto his brother's wife, that he spilled it on the ground, lest he should give seed to his brother.