Mishnayos Gittin Perek 4 Mishnah 5

In the case of one who is a half-slave half-freeman because only one of his two owners emancipated him, he serves his master one day and serves himself one day; this is the statement of Beit Hillel. Beit Shammai say: Through such an arrangement you have remedied his master, as his master loses nothing through this. However, you have not remedied the slave himself, as the slave himself remains in an unsustainable situation. It is not possible for him to marry a maidservant because he is already a half-freeman, as it is prohibited for a freeman to marry a maidservant. It is also not possible for him to marry a free woman, as he is still a half-slave. If you say he should be idle and not marry, but isn’t it true that the world was created only for procreation, as it is stated: “He did not create it to be a waste; He formed it to be inhabited” (Isaiah 45:18)? Rather, for the betterment of the world his master is forced to make him a freeman, and the slave writes a promissory note accepting his responsibility to pay half his value to his master. And Beit Hillel ultimately retracted their opinion, to rule in accordance with the statement of Beit Shammai, that a half-slave must be set free.

מִי שֶׁחֶצְיוֹ עֶבֶד וְחֶצְיוֹ בֶן חוֹרִין, עוֹבֵד אֶת רַבּוֹ יוֹם אֶחָד וְאֶת עַצְמוֹ יוֹם אֶחָד, דִּבְרֵי בֵית הִלֵּל. אָמְרוּ לָהֶם בֵּית שַׁמַּאי, תִּקַּנְתֶּם אֶת רַבּוֹ, וְאֶת עַצְמוֹ לֹא תִקַּנְתֶּם. לִשָּׂא שִׁפְחָה אִי אֶפְשָׁר, שֶׁכְּבָר חֶצְיוֹ בֶן חוֹרִין. בַּת חוֹרִין אִי אֶפְשָׁר, שֶׁכְּבָר חֶצְיוֹ עָבֶד. יִבָּטֵל, וַהֲלֹא לֹא נִבְרָא הָעוֹלָם אֶלָּא לִפְרִיָּה וְלִרְבִיָּה, שֶׁנֶּאֱמַר (ישעיה מה) לֹא תֹהוּ בְרָאָהּ, לָשֶׁבֶת יְצָרָהּ. אֶלָּא מִפְּנֵי תִקּוּן הָעוֹלָם, כּוֹפִין אֶת רַבּוֹ וְעוֹשֶׂה אוֹתוֹ בֶן חוֹרִין, וְכוֹתֵב שְׁטָר עַל חֲצִי דָמָיו. וְחָזְרוּ בֵית הִלֵּל לְהוֹרוֹת כְּדִבְרֵי בֵית שַׁמָּאי: