Presenting a gift to God demands a profound sense of respect, awe, and absolute perfection. To offer a flawed sacrifice is to display contempt toward Heaven. Conceptually, this restriction directly follows earlier prohibitions against planting sacred trees or erecting idolatrous pillars. Just as external flaws in the environment and structure of the altar are forbidden, so too are internal flaws within the sacrifices placed upon it [טור הארוך, חזקוני, בכור שור].
The specified animals, cattle and flocks [ביאור שטיינזלץ], carry deep symbolic weight. The ox represents human action and labor, while the sheep symbolizes destiny and submission. Both aspects of human life must be dedicated to God in absolute purity, without any defect [רש״ר הירש].
Although the prohibition against offering blemished animals already appears in the book of Leviticus, it is repeated here as a direct warning to the ordinary Israelite bringing the offering. The priests, having been warned previously, are already highly skilled and cautious in their duties [רמב״ן, ביאור יש״ר]. The precise phrasing expands the scope of the restriction. It includes animals born with defects, those suffering from temporary conditions like scabs, and even an animal with a limb that medical experts determine must be amputated in the future, even if the cut has not yet occurred [אור החיים, תורה תמימה, רלב״ג, מלבי״ם]. Beyond the physical state of the animal, the demand for perfection extends to the person making the offering. The individual must approach the altar with a clean soul, completely free from sinful thoughts [שפתי כהן].
The prohibition also encompasses any bad element, a concept that commentators understand through three complementary approaches. First, it serves as an extension of physical blemishes, disqualifying animals that suffer from conditions not officially classified as defects but which render them unsightly or unfit, such as illness, extreme old age, or severe filth [אבן עזרא, ביאור שטיינזלץ, תורה תמימה, אדרת אליהו]. Second, it points to moral and spiritual disqualifications, forbidding the use of animals that were involved in severe transgressions, such as idolatry, being used as a prostitute's fee, or bestiality [רלב״ג, רש״ר הירש].
The primary approach among commentators connects this concept to speech. It serves as a warning against invalidating a sacrifice through improper words spoken during the slaughter, such as expressing an intention to eat the meat outside of its permitted time or location [רש״י, רמב״ן, מזרחי, מלבי״ם]. Within this perspective, a subtle debate exists. Some maintain that a sacrifice is only invalidated if these improper intentions are explicitly spoken aloud [יריעות שלמה]. Others emphasize that even a negative thought held silently in the heart is sufficient to ruin the offering [מזרחי, דברי דוד, ברכת אשר].
Ultimately, presenting such an offering is declared an abomination. The physical blemish itself is not the abomination; rather, the very act of bringing a flawed gift before God is deeply offensive and carries a punishment [אבן עזרא, ביאור שטיינזלץ]. This severe designation also serves to exclude other unfit animals, such as crossbreeds or those with fatal injuries [תורה תמימה]. Finally, the law makes two vital distinctions regarding this abomination. First, the disqualification applies only to the tainted animal itself, while its offspring remain entirely permitted for use. Second, the permanent stain of the abomination applies exclusively to the animal, not the human being. While an animal involved in a sin is forever barred from the altar, a priest who has sinned retains the ability to repent and be fully restored to his sacred service [תורה תמימה, צפנת פענח, מלבי״ם].