Halakhah for Horayot 25:25

From the laws of the commandment is that which they said (Gittin 39a) that the order of the communal reading of the Torah is like this - that the priest (Kohen) always reads first; and a Levite after him; and an Israelite after him. But if there is no priest there, the package is undone. And if there is no Levite, a priest reads twice. But a priest does not read after a priest, because of [the appearance of] the defect of the first. And a Levite does not read after a Levite, because of [the appearance of] the defect of both of them. And this honor is done for them if they are fitting it. But if they are sinners, we prevent them from honor. And they, may their memory be blessed, already said (Horayot 13a) that a mamzer Torah scholar precedes an ignoramus high priest. But today at this time, we have not seen [anyone] who had himself precede any priest, because of his wisdom - and 'following modesty is the fear of the Lord.' And the rest of its details are elucidated in scattered places of the Gemara: Makkot; Chullin; Bekhorot; Shabbat; and the rest of them (see Mishneh Torah, Laws of Vessels of the Sanctuary and Those who Serve Therein 8).

That a mamzer (a child born from a forbidden marriage) should not marry a daughter of Israel: That a mamzer is prevented from marrying a daughter of Israel. And about this is it stated (Deuteronomy 23:3), "No mamzer shall come into the congregation of the Lord," meaning to say that he should not come to marry a woman from the daughters of the congregation of the Lord. But it is truly permissible for him to enter with them into all of their places of residence and to give and take with them in all things [just] like [any other] one of the children of Israel. And they, may their memory be blessed, have already said (Horayot 13a) that a mamzer Torah scholar precedes a ignoramus Kohen (priest) in the reading of the Torah (see Rambam on Mishnah Gittin 5:7).