א מִי שֶׁיֵּשׁ לוֹ אָח מֵאָבִיו, אֲפִלּוּ הוּא מַמְזֵר אוֹ עוֹבֵד ע" א, וַאֲפִלּוּ הוּא קָטָן, מִשֶּׁיָּצָא רֹאשׁוֹ וְרֻבּוֹ לַאֲוִיר הָעוֹלָם קֹדֶם שֶׁיָּמוּת אָחִיו, הֲרֵי זֶה זוֹקֵק (פי', קוֹשֵׁר, מֵעִנְיָן "אֲסוּרִים בַּזִּקִים") (אִיּוֹב לו, ח) אֶת אִשְׁתּוֹ לְיִבּוּם. אֲפִלּוּ הוּא גּוֹסֵס אוֹ פְּצוּעַ מַכּוֹת שֶׁאֵינוֹ יָכוֹל לִחְיוֹת מֵהֶם, לֹא תִּנָּשֵׂא כָּל זְמַן שֶׁהוּא חַי. אֲבָל אִם הוּא אָחִיו מֵאִמּוֹ, אוֹ שֶׁנּוֹלַד אַחַר מוֹתוֹ, יְבִמְתּוֹ מֻתֶּרֶת לַשּׁוּק. וְכֵן אִם הָיָה לוֹ אָח מֵהַשִּׁפְחָה אוֹ מֵהַנָּכְרִית, אֵינוֹ זוֹקֵק אֶת אִשְׁתּוֹ, אַף עַל פִּי שֶׁהָיְתָה לֵדָתוֹ בִּקְדֻשָּׁה, הוֹאִיל וְהוֹרָתוֹ הָיְתָה שֶׁלֹּא בִּקְדֻשָּׁה:
1 One who has a brother of the same father, even if he is a bastard or an apostate, even if he is a child, [the law is that] from the point that his head and most of his body already was born before his brother died, behold he is tied Rema: [Zokek] meaning "tied", like (Job 36:8) to his [brother's] wife in levirate marriage. Even if he is on his deathbed, or diseased so much so that he will not live because of it, she cannot remarry [to someone else] so long as he lives. But if it is a brother of the same mother, or he was born after [the married childless brother] died, his "yibbum" can remarry [lit. "permitted to the marketplace"]. Similarly, if [the married childless brother] has a brother from a maid-servant, or a gentile woman, he is not tied to his [brother's] wife in levirate marriage, even though he was born in holiness, since his conception was not in holiness.