Yoreh Deah Siman 267 Seif 7

 

ז כְּשֶׁיִּשְׁתַּחְרֵר הָעֶבֶד צָרִיךְ טְבִילָה אַחַר כָּךְ בִּפְנֵי שְׁלֹשָׁה, וְאֵין צָרִיךְ לְקַבֵּל עָלָיו מִצְוֹת וּלְהוֹדִיעוֹ עִקָּרֵי הַדָּת, שֶׁכְּבָר הוֹדִיעוּהוּ כְּשֶׁטָּבַל לְשֵׁם עַבְדוּת.

 

Seif 7

 

When a slave is released we immerse before three witness, he does not need to accept upon himself the commandments nor do we inform him of the fundamentals of the faith, because he was already informed when we immersed him for slavery.