Desecrating the Name of G‑d

"And you shall not profane My holy name"Leviticus 22:32.

We are commanded not to desecrate G‑d's Name. This mitzvah has three applications:

a) Martyrdom: If an oppressive government arises and sets for itself the goal of eradicating Judaism and Torah, we are commanded to sacrifice our lives rather than deviate one iota from Jewish law or custom. And, at any time, we are obligated to allow ourselves to be killed rather than transgress one of the three cardinal sins—idolatry, murder, and certain forbidden sexual relations (such as adultery, incest, and homosexuality).

One who allows himself to be martyred under these circumstances has sanctified G‑d's Name. One who transgresses, has desecrated His Name.

b) Sins of Spite: One who transgresses G‑d's command not for pleasure or for the sake of perceived benefit, but simply to demonstrate indifference for G‑d's words, has desecrated G‑d's Name, having displayed open disregard for His wishes.

c) Behavior Befitting a Torah Scholar: One who is renowned for his piety may not do anything that even smells of impropriety—even if there is no transgression involved. One Talmudic rabbi said that if he were to take meat from the butcher on credit, without paying immediately, that would constitute a desecration of G‑d's Name. When a Torah scholar behaves in exemplary fashion, this causes G‑d's Name to be sanctified—and vice versa.

Destroying a Place of Worship

"This you shall not do to the L-rd your G‑d"Deuteronomy 12:4.

We are forbidden from destroying G‑d's houses of worship (i.e. the Holy Temple), or any of its utensils—such as the altar or any part of the sanctuary. This prohibition also includes defacing the books of the Prophets or erasing any written Name of G‑d.

Heeding a Prophet

"You shall listen to him"Deuteronomy 18:15.

We are commanded to obey the instructions of a prophet. This as long as he doesn't instruct to permanently abolish any mitzvah. But we are commanded to listen to a prophet if he tells us to temporarily suspend the observance of a biblical precept.