“[A bull, a sheep, or a goat, when it is born,] shall be seven days under its mother.” Why seven days? So it can be examined, as if its mother gored it or if a blemish is found in it, it is unfit and it will not be fit for an offering, as we learned there: After the birth of an offspring by caesarean section, [the mother] does not observe days of impurity and days of purity, and she is not obligated to bring for it the offering.
Rabbi Shimon said: It is considered naturally born.18Mishna Nidda 5:1. According to the first tanna, a child born through caesarean section is not considered to have come into the world through a normal birth process, such that the laws that normally apply to a woman who has given birth would apply. Similarly, when the verse states that a bull, sheep, or goat was “born,” the implication is that they were born naturally and not through caesarean section.
Since the normal birth process can lead to injury, the animal is given seven days so that it can be certain it has suffered no blemishes before bringing it as an offering. Another matter, “it…shall be seven days under its mother.” Rabbi Yehoshua of Sikhnin said in the name of Rabbi Levi: This is analogous to a king who entered a province and issued an edict: ‘All the guests who are here shall not have an audience with me until they have an audience with the queen first.’
So, the Holy One blessed be He said: ‘Do not bring an offering before Me until Shabbat will pass for it, as there are no seven days without Shabbat, and there is no circumcision without Shabbat.’ That is what is written: “From the eighth day on, it shall be accepted.” Rabbi Yitzḥak said: The law of man and the law of animal are the same. The law of man: On the eighth day, the flesh of its foreskin shall be circumcised” (Leviticus 12:3).
The law of animals: “From the eighth day on, it shall be accepted.” In other words, if you brought an offering before Me of your own volition and with good will, it is My offering. If it is by force and against your will, I will not ascribe to you as though you sacrificed before Me, but rather, as a “fire offering to the Lord” (Leviticus 22:27).19By using the term fire offering [isheh] rather than offering [korban] or My offering [korbani], the implication is that the individual views it as a waste that the animal is burned in fire.
Similarly, “Command the children of Israel, and say to them: My offering, My food, for My fires” (Numbers 28:2) – if you brought an offering before Me of your own volition and with good will, it is “My offering.” If it is by force, it is to “My fires” and not to the Name.