170. Hazardous Materials

Avodas Kochavim 9:8

Just as it is prohibited to sell idolators things to assist them in idolatry, it is prohibited to sell them things that can pose a public menace, like bears, lions, weapons, and manacles. One is likewise not permitted to sharpen their weapons. Anything that one may not sell to an idolator may also not be sold to a Jew if there is reason to suspect that he will sell it to idolators. One may likewise not sell hazardous items to a Jew who is a bandit.

Avodas Kochavim 9:9

When Jews live among idolators and have a pact with them, it is permitted to sell weapons to the servants of the king and to his soldiers. This is because they use these things to fight the country’s enemies and to protect it. In this way, they protect the entire population, Jewish and idolatrous alike.

One may walk outside a city that has an idol in it but he may not enter it. If the idol is outside the city, he may enter it.