The 298th prohibition is that we are forbidden from leaving obstacles or dangerous objects in our land and in our houses, in order not to endanger people.

The source of this prohibition is G‑d's statement1 (exalted be He), "Do not place blood2 in your house."

In the words of the Sifri, "The phrase 'You must place a guard-rail' constitutes a positive commandment;3 and the phrase 'Do not place blood' constitutes a prohibition."

The details of this mitzvah are explained in the beginning of tractate Shekalim in the Jerusalem Talmud and in a number of passages in Seder Nezikin.4