א מִצְוַת עֲשֵׂה עַל הָרַב לָמוּל עֲבָדָיו. עָבַר הָרַב וְלֹא מָלוֹ, מִצְוָה עַל בֵּית דִּין לְמוּלוֹ. אֶחָד עֶבֶד שֶׁנּוֹלַד בְּבֵית יִשְׂרָאֵל, וְאֶחָד שֶׁקְּנָאוֹ מֵהָעוֹבֵד כּוֹכָבִים, חַיָּב לְמוּלוֹ. וְאֵינָם נִמּוֹלִים אֶלָּא בַּיּוֹם. וִילִיד בַּיִת נִמּוֹל לְח’, וּמִקְנַת כֶּסֶף נִמּוֹל בַּיּוֹם שֶׁנִּלְקַח, אֲפִלּוּ לְקָחוֹ בַּיּוֹם שֶׁנּוֹלַד, נִמּוֹל בְּיוֹמוֹ.
It is a positive commandment for a master to circumcise his slaves, If the master fails to circumcise them then it is a mitzvah on the Beit Din to circumcise them. A slave boy born in a Jewish household or one purchased from an idolater, you are (still) required to circumcise. A slave not born in your home is circumcised the same day, even if you acquired him the day he was born, you circumcise him the same day.
וְיֵשׁ מִקְנַת כֶּסֶף שֶׁנִּמּוֹל לְח’, וְיֵשׁ יְלִיד בַּיִת שֶׁנִּמּוֹל לְאוֹתוֹ יוֹם שֶׁנּוֹלַד. כֵּיצַד, לָקַח שִׁפְחָה וְעֻבָּרָהּ עִמָּהּ, וְיָלְדָה, הֲרֵי זֶה נִמּוֹל לִשְׁמוֹנָה. וְאַף עַל פִּי שֶׁלָּקַח הָעֻבָּר בִּפְנֵי עַצְמוֹ, וַהֲרֵי הָעֻבָּר מִקְנַת כֶּסֶף, הוֹאִיל וְלָקַח אִמּוֹ קֹדֶם שֶׁנּוֹלַד, נִמּוֹל לִשְׁמוֹנָה.
There are slaves who are purchased that are circumcised on the eighth day as well as slaves born in your home that you circumcise the same day. What do we mean?
Should one purchase a maidservant and purchase the rights to her fetus (separately), when she gives birth, the baby should be circumcised on the eighth day.
Although the fetus itself was purchased alone, since he purchased the mother before the child was born, the child should be circumcised on his eighth day.
לָקַח שִׁפְחָה לְעֻבָּרֶיהָ, אוֹ שֶׁלָּקַח שִׁפְחָה עַל מְנַת שֶׁלֹּא לְהַטְבִּילָהּ לְשֵׁם עַבְדוּת, אַף עַל פִּי שֶׁנּוֹלַד בִּרְשׁוּתוֹ נִמּוֹל בַּיּוֹם שֶׁנּוֹלַד, שֶׁהֲרֵי הַנּוֹלָד הַזֶּה כְּאִלּוּ הוּא מִקְנַת כֶּסֶף לְבַדּוֹ, וּכְאִלּוּ הַיּוֹם קְנָאוֹ, שֶׁאֵין אִמּוֹ בִּכְלַל שִׁפְחוֹת יִשְׂרָאֵל, כְּדֵי שֶׁיִּהְיֶה הַבֵּן יְלִיד בַּיִת.
If one acquires a maidservant or her offspring or one acquires (purchases) a maidservant with the intent of not immersing her for the sake of slavehood, even though her offspring is born in his home, the child should be circumcised on the day he was born,
This is because the child is considered as if he alone had been purchased , and it is as if he purchased him this day.
His mother is not among the maidservants of the Jewish people, so that the child could be considered home-born slave.
וְאִם טָבְלָה אִמּוֹ אַחַר שֶׁיָּלְדָה, הֲרֵי זֶה נִמּוֹל לִשְׁמוֹנָה.
And if she immerses after she gives birth, the child should be circumcised on the eighth day.