"and I will do the same (31) You shall not do thus to the L-rd your G-d": Subsumed herein is (service) for idolatry, and service for the altar (in the Temple) — whence they ruled: A type of service which they use for idolatry is forbidden (to a Jew) for idolatry. If he performed the like (for idolatry) he is liable (to the death penalty). And the like is forbidden (to a Jew) for the altar. If he performed the like for the altar, he is not liable (to the death penalty).
I might think that if they sacrifice (to idolatry) sin-offerings and guilt-offerings, it is forbidden to do the same for the altar; it is, therefore, written (21) "For every abomination of the L-rd, which He hates, did they do unto their gods" — Scripture intends (to forbid [for the altar]) only things which the Holy One Blessed be He hates. (Ibid. 31) "For even their sons and their daughters did they burn in fire to their gods. This tells me only of their sons and their daughters. Whence do I derive (that they did the same to) their fathers and their mothers? From "for even their sons and their daughters." R. Yaakov says; I saws a Canaani who bound his father before his dog — which ate him.