The background of Leviticus is important to understand. The people are being told not to act like the "pagans". This is also the format Paul uses in Romans. "You shall not lie with a male as one lies with a female; it is an abomination." These words occur solely in the Holiness Code of Leviticus, a ritual manual for Israel's priests. This prohibition of supposedly homosexual acts follows after the prohibition of the idolatrous sexuality of worshipping Molech, whose cult included male cult prostitutes and bestiality. Lev 18 is specifically designed to distinguish the Jews from the pagans who worshipped the multiple gods of fertility cults. It also is included with other Mosaic laws such as required killing kids who curse their parents, the death penalty for picking up sticks or doing other work on the Sabbath, and under the law, slave-beating was a protected legal right!

From a Jewish prospective, the commandments given at Sinai, including those of Leviticus (in Hebrew Jews simply name a book after the first word that appears - "V'yikra" - which means "then he spoke") were given to the Jewish people. Since they were only commanded to Jews, no one who is not Jewish need worry about obeying them. Judaism holds God taught basic laws to all humanity before Sinai (no murder, rape, etc), but that the more specific laws such as in Leviticus, apply only to Jews.

Lev 20:13 is giving the penalties for the Lev 18:22 "abomination" or in the Hebrew "toevah" Unlike what the English translation implies, toevah did not usually signify something intrinsically evil, but something ritually unclean for Jews. Eating pork, shellfish, lobster, eating meat 3 days old, trimming beards, etc is just as much an "abomination". It is used throughout the OT to designate those Jewish sins which involve ethnic contamination or idolatry. In many other OT verses it simply means idolatry. Lev 18 is specifically designed to distinguish the Jews from the pagans among whom they had been living. The prohibition of supposedly homosexual acts follows after the prohibition of idolatrous sexuality of worshipping Molech, whose cult included male cult prostitutes and bestiality.

Chapter 20 begins with a prohibition of sexual idolatry almost identical with this, and like 18, its manifest purpose is to elaborate a system of ritual "cleanliness" whereby the Jews will be distinguished from neighboring peoples. This was also the interpretation given by later Jewish commentaries such as those of Maimonides. Boswell also references much Jewish historic discussion about the non practice of the death penalty which is also mandated for violating the Sabbath, cursing one's parents and many infractions listed in the Talmud.