Leviticus 27:10 - Sacred swaps forbidden forever.

Context in Vayikra (Leviticus 27:10)

The verse discusses the laws of temurah (substitution), which apply when one attempts to exchange an animal consecrated as a sacrifice for another animal. The Torah strictly prohibits such exchanges and declares that both the original consecrated animal and its substitute become sanctified.

Rashi's Explanation

Rashi (Vayikra 27:10) clarifies that the prohibition applies whether one attempts to substitute a better animal for a worse one (tov b'ra) or a worse animal for a better one (ra b'tov). Even if the exchange is made, the original sanctity remains, and the substitute also becomes holy. Rashi emphasizes that this law teaches the irrevocable nature of sanctification—once an object is dedicated to Hashem, human intervention cannot nullify its holiness.

Rambam's Legal Perspective

In Hilchos Temurah (1:1), the Rambam codifies this law, stating that one who attempts to substitute a consecrated animal violates a negative commandment. The Rambam further explains (1:3) that the sanctity transfers automatically, even if the substitution was unintentional or done in error, reinforcing the principle that kedushah (holiness) is not subject to human manipulation.

Talmudic Discussion (Temurah 17a)

The Gemara derives from this verse that the prohibition of temurah applies only to animals designated for sacrifices, not to other forms of consecrated property. The Sages learn from the phrase "v'hayah hu u'temurato" ("it and its substitute") that both animals assume sanctity, illustrating that the original dedication cannot be undone.

Midrashic Insight (Vayikra Rabbah 27:10)

The Midrash connects this law to the broader theme of commitment to mitzvos. Just as one cannot retract a vow to Hashem, one cannot nullify the sanctity of a dedicated offering. This teaches the importance of sincerity in avodas Hashem (divine service) and the gravity of pledges made to the Beit HaMikdash.

Practical Implications

• The prohibition applies whether the exchange is verbal ("This animal shall replace that one") or physical (attempting to switch the animals).
• Both the original and substitute animals must be treated as consecrated, though only one may be offered as a sacrifice.
• This law underscores the permanence of kedushah and the seriousness of vows in Jewish law.