Law for the Protection of German Blood and Honor, September 15, 1935 (RGB1 I,1146.)
Implication : “He that is born in thy house, and he that is bought with thy money, must needs be circumcised: and my covenant shall be in your flesh for an everlasting covenant.” (Gen. 17: 13).
We can see this practice from Maimonides Issurei Biah 14:9 which states :
“When a servant is purchased from the gentiles, we do not say: "Why did you choose to convert? "[1] Instead, we say to him: "Do you desire to enter the category of Jewish servants and become one of
If he does not desire to accept [the status of a servant], we are patient with him for twelve months. Afterwards, we sell him to a gentile. It is forbidden to maintain him for a longer period.[3] If at the outset,
[2]A male servant is also circumcised before conversion. It is questionable why the Rambam does not mention this point.
[4] [The Rama (Yoreh De'ah 267:4) writes that in the lands where he lived (Central Europe), it was forbidden to convert a gentile to Judaism. Therefore it is taken for granted that the servant was purchased
Taken from chabad.org/library/articl…
21.21 Notwithstanding, if he continue a day or two, he shall not be punished: for he is his money.”
“19.20 And whosoever lieth carnally with a woman, that is a bondmaid, betrothed to an husband, and not at all redeemed, nor freedom given her; she shall be scourged; they shall not be put to death, because she was not free.
See this in contrast to another slavery law in Ex. 21:4