Sifrei Mitzvot untuk Ulangan 23:8

These [people] it is not appropriate to marry [them] either because of a disqualification in their lineage or because of something physical or because of [something] illicit. A male Israelite is forbidden to marry a Mamzer, or a Netin who is from the Gibeonites that Joshua decreed against marrying them. There is a prohibition against marrying an Ammonite, Moabite and, Egyptian. [Marrying a] Mamzer or Netin, is an eternal prohibition for all generations and it makes no difference whether they're male or female. Male Ammonites and Moabites are eternally prohibited but the females are immediately permitted. Egyptians and Edomites, males and females, are prohibited for the first two generations, after an [Egyptian father] converts, he and his son are prohibited but the [Egyptian father's] grandson is permitted. A pregnant Egyptian woman who converts, her son is a second generation Egyptian. A male Israelite who copulates with one of these [mentioned above], the child is like her [ s/he has the mother's lineage], however one of those [mentioned above], except for a Mamzer, who copulates with an Israelite woman, the child may marry in to the community although it is disqualified for the priestly lineage. If a female of one of these [mentioned above] converted and married an Israelite or a male of one these [mentioned above] converted an Israelite woman, the child take the lineage of the [more] disqualified one therefore a converted second generation Ammonite or Egyptian convert who married an Israelite woman their daughter is accepted for no matter which one of them [i.e. her parents] we follow she is acceptable even for [marriage into] the priesthood even though her copulation was a transgression. A second-generation male Egyptian who marries a first-generation Egyptian woman, his son is a second-generation [Egyptian]; a first-generation Egyptian man who marries a second-generation Egyptian woman, his sone is a third-generation [Egyptian] for it all follows the mother. An Ammonite male who married an Egyptian female their child is an Ammonite, an Egyptian male who married an Ammonite female their child is an Egyptian for among the nations [in matters of lineage] we follow the males. If they converted then the child follows the more deficient of the two of them. For example an Amonite male convert who follows an Egyptian female convert or an Egyptian male convert who married an Ammonite femal convert and they gave birth to a son his status becomes an Ammonite who is eternally prohibited, if they gave birth to a daughter her status is Egyptian who is prohibited for two generations. Regarding all other nationalities, immediately after converting they have the status of an Israelite immediately. Rambam wrote that in our time both an Egyptain and an Ammonite are permitted [to marry an Israelite] immediately [after conversion] for Sennacherib arose and intermixed all of the nations and anything removed [from a mixture is viewed as if it was] removed from the majority [of the mixture] and we estimate the [individual convert] descends from the majority of nations who are permitted. My master and father the Rosh wrote that Ammonites, Moabites and Edomites are immediately permitted but also now Egyptians are prohibited [after conversion] until the third generation. A male slave who was immersed [by his Jewish master] for the purpose of becoming a [Canaanite] slave is prohibited form marrying an Israelite woman, and an Israelite man is prohibited from marrying a female slave who was immersed [by her Jewish master] for the purpose of becoming a [Canaanite] female slave, regardless of whether she was his slave or another's [slave]. However, after his master frees him, or abandons him, or lays phylacteries on him, or if his master was a prayer leader and called him to go up to the Torah [ for an aliyah] behold he comes like an Israelite in all matters but if he lay phylacteries in the presence of his master or called him or read the Torah in his presence [during an aliyah] he does not go out to freedom. If his master married him off to an Israelite woman or even if he married an Israelite woman in the presence of his master, the betrothal takes effect for certainly he [his master] has released him since he permitted him to marry an Israelite woman and certainly if it is he [the master] who is marrying his own female slave that betrothal with her takes effect. Who is a Mamzer? It is [the offspring] of a man who copulates with one of the illicit [unions] where the punishment is death administered by the [earthly] Beth Din or Kritut [death / childlessness by the Heavens] with the exclusion of one who copulated with a Niddah who is not a rabbinic Mamzer. Rambam wrote that if her husband was overseas and she gave birth then the child is is presumed to have the status of a Mamzer for a fetus does not stay in its mother's womb for more than twelve months but the Behag wrote that the child is not presumed to have the status of a Mamzer for we attribute it to the possibility that maybe her husband arrived [home] discreetly and copulated [with her]. A married woman who gained a reputation of copulating promiscuously while under [marriage] to her husband and everyone is chattering about her, we need not worry about her children that maybe they are Mamzerim for we excuse it and say that the majority of instances of intercourse takes place with the husband but as for her we suspect her of being a promiscuous woman [zonah] and if she is exceedingly promiscuous then we are even concerned about [the Mamzer status] of her children.

If a Jewish person sleeps with a non-Jew in the way of married people, they receive biblically ordained lashes, as it says “You shall not intermarry with them: do not give your daughter to their sons or take their daughters for your sons.” (Deuteronomy 7:3) The same law is true concerning the seven nations of the land of Canaan and all other nations. This is also explained by Ezra, “We will not give our daughters in marriage to the peoples of the land, or take their daughters for our sons.” (Nehemiah 10:31)

i.e. The illegitimate children of a Hebrew servant and Caanite maid-servant are not considered Jews. Because of this, his father's seed was wasted because it did not go toward the birth of another Jew. This is said in Deuteronomy 23:18, "No Israelite man or woman shall become a temple prostitute."