Noah Builds an Altar and the Laws of Lawful Offerings

"And Noah built an altar" (Genesis 8:20). Noah reflected: why did the Holy One, blessed be He, command more of the clean animals than of the unclean? Only because He wishes to offer from them. At once, "And he took of every clean animal and offered burnt offerings on the altar"? upon the great altar in Jerusalem, where Adam the first man had offered, as it is said, "And it shall please the LORD better than an ox or a bullock" (Psalms 69:32). Until the Tabernacle was erected, the high places were permitted, and the service was performed by the firstborn, and all were fit to be offered: beast, wild animal, and bird; males and females; unblemished and blemished; clean but not unclean. And all were offered as burnt offerings. A burnt offering that Israel offered required flaying and cutting into pieces, and gentiles in the present time are permitted to do likewise. From where are these matters derived? Rav Huna said: because Scripture states, "And Noah built an altar to the LORD" and so on. Beast and bird are as their plain meaning; wild animal is included in the category of beast; males and females, unblemished and blemished? wholeness and maleness apply to beasts, but wholeness and maleness do not apply to birds; blemished, to exclude one missing a limb, which is not [valid]. For Rav Elazar said: from where do we know that an animal missing a limb is forbidden to the sons of Noah? As it is written, "And of all that lives" and so on, as written above (in remez 54). "Clean but not unclean"? but did clean and unclean exist at that time? Rav Shmuel bar Nahman said in the name of Rav Yonatan: from those that were destined to become clean. How did he know? Rav Hisda said: he passed them before the ark; whichever the ark accepted was clean. Rabbi Abbahu said: those that came of their own accord. All were offered as burnt offerings, in accordance with the one who says peace offerings were not offered by the sons of Noah. And gentiles in the present time are permitted to do this, for the rabbis taught: "Speak to the children of Israel" (Leviticus 17:2)? the children of Israel are commanded concerning slaughter outside, but the gentiles are not commanded. Therefore each one may go and build a high place for himself and offer upon it whatever he wishes; and it is forbidden to assist them, and forbidden to act as their agent, but to instruct them is permitted. Rabbi Yosei says: one who offers outside is not liable until he raises it to the top of the altar. Rabbi Shimon says: even if he raised it only upon a rock or upon a stone, he is liable. Rav Huna said: what is the reason of Rabbi Yosei? Because it is written, "And Noah built an altar to the LORD." Rabbi Yohanan said: what is the reason of Rabbi Shimon? Because it is written, "And Manoah took the kid of the goats and offered it up upon the rock to the LORD" (Judges 13:19). And the other? Is it not written, "And Noah built an altar"? that was mere elevation. And the other? Is it not written, "And Manoah took"? that was a ruling for the hour. And some say, this is the reason of Rabbi Shimon: as it is written, "the altar... at the entrance of the tent of meeting," and there is no [requirement of an] altar on a high place.