One should not sell them bears, lions or anything which may injure the public.
One should not join them in building a basilica, a scaffold, a stadium, or a platform.
But one may join them in building pedestals for altars and also private baths.
When however he reaches the cupola in which the idol is placed he must not build.
It is permitted to go to stadiums, because by shouting one may save the victim. One is also permitted to go to a camp for the purpose of maintaining order in the country, providing he does not conspire with the Romans, but for the purpose of conspiring it is forbidden.
It has been taught: One should not go to stadiums because they are ‘the seat of the scornful’, but R. Nathan permits it for two reasons: first, because by shouting one may save the victim, secondly, because one might be able to give evidence of death for the wife of a victim and so enable her to remarry.
Our Rabbis taught: Those who visit stadiums or a camp and witness there the performance of sorcerers and enchanters, or of bukion and mukion, lulion and mulion, blurin or salgurin — lo, this is ‘the seat of the scornful,’ and against those who visit them Scripture says, Happy is the man that hath not walked in the counsel of the wicked . . . nor sat in the seat of the scornful, but his delight is in the law of the Lord. From here you can infer that those things cause one to neglect the Torah.