The purity of the altar and the perfection of the sacrifices demand absolute strictness regarding both the physical and spiritual integrity of the animals offered. This standard transcends national boundaries, applying equally to sacrifices originating from outside the Israelites. When a foreigner wishes to bring an offering to the Temple, the same rigorous rules apply. Although non-Jews are generally not restricted from offering blemished animals on their own altars—provided the animal is not missing a limb—God's altar cannot accept a flawed sacrifice, regardless of who brings it. Flawless animals may be accepted from foreigners as freewill offerings, but blemished ones are firmly rejected [רש״י, תורה תמימה, הופמן, ברטנורא]. Alternatively, this restriction serves as a warning to Israelites purchasing animals from foreigners. An Israelite might mistakenly assume that because a non-Jew is permitted to castrate an animal, a castrated beast purchased from them would be acceptable for the altar. The Torah clarifies that such an animal remains strictly forbidden [שד״ל, ביאור יש״ר].
The types of sacrifices that may be accepted from foreigners are specifically limited. They may bring burnt offerings as vows or freewill gifts, but they cannot bring peace offerings, as they do not possess the spiritual standing required to partake in a shared meal from the divine table. Similarly, they cannot bring sin or guilt offerings, as they are not bound by the specific commandments that necessitate them [רלב״ג, מלבי״ם, ריב״א]. Furthermore, the prohibition extends beyond individual offerings to communal ones. Neither funds nor animals may be accepted from foreigners for any of Israel’s public sacrifices, even if the animals are absolutely flawless [מזרחי, תורה תמימה, גור אריה, אדרת אליהו].
The underlying reason for disqualifying these animals is rooted in the concept of corruption and destruction [רש״י, אבן עזרא, ברכת אשר]. A hidden flaw, such as castration, ruins the animal's natural perfection and its reproductive capacity [ספורנו, ביאור יש״ר]. This prohibition against castration applies equally to female animals [תורה תמימה, מלבי״ם, אדרת אליהו]. Even if a castrated animal grows fatter and physically superior as a result of the procedure, it remains fundamentally flawed and invalid for the altar [בכור שור]. However, this disqualification lasts only as long as the blemish is actively present; if the flaw heals entirely, the animal once again becomes valid for an offering [תורה תמימה, פרדס יוסף].
On a deeper level, the concept of corruption in the Torah is frequently associated with idolatry and sexual immorality. Just as a physical defect disqualifies an animal, a moral defect—such as an animal used for idol worship or involved in a sinful act of bestiality—renders it entirely unfit for the altar [תורה תמימה, רלב״ג, הופמן]. The demand for an unblemished animal symbolizes absolute, unyielding devotion to God. A physical blemish represents a deficiency in this devotion, which is the very root of idolatry and immorality, perfectly intertwining physical flaws with moral corruption [רש״ר הירש].
Ultimately, these flawed sacrifices will not be accepted willingly and cannot provide atonement [רש״י, מזרחי, גור אריה]. The rejection of these offerings specifically affects the Israelites involved. This may refer to an Israelite who purchased the animal from a foreigner [שד״ל]. Alternatively, while the foreigner incurs no sin for bringing a blemished animal—since they are not commanded otherwise—the Israelite who actually performs the sacrifice on their behalf derives no merit or atonement from the act [ביאור יש״ר]. Bringing such an offering is inherently improper, ensuring it will never be desired by God [ביאור שטיינזלץ].