And the 144th prohibition is that we are forbidden from eating an unblemished firstborn animal outside of Jerusalem.

The source of this commandment is G‑d's statement,1 "In your own settlements you may not eat ... the firstborn of your cattle."

The Sifri says, "The word Bechoros refers to the firstborn animal. This verse teaches that a non-priest who eats from a firstborn animal, whether before or after the blood has been sprin­kled,2 transgresses a prohibition."

It has been made clear to you that this prohibition includes two parts: that a non-priest is forbidden from eating an unblem­ished firstborn animal, and that a priest is forbidden from eating it outside Jerusalem. In both cases the prohibition applies only if the firstborn animal is unblemished.3

One who transgresses this prohibition is punished by lashes.